4. Facilitating Resource Management Category

4.1 FRM 220

Programme Title:

Stock unit system

Programme Leader:

Prof Keith Woodford

Institution:

Lincoln University

Research Programme not yet completed and reported at time of the preparation of this publication. Will be reported in next Research Results publication.

4.2 FRM 221

Programme Title:

Biodiversity conservation

Programme Leader:

Steve Wratten

Institution:

Lincoln University

Summary

The programme goals are (a) to quantify native and non-native invertebrate, plant and bird bidiversity on Canterbury and East Cape cropping land and field margin/shelterbelt habitats, and to assess the contribution of this biodiversity to ecosystem function; (b) to model the aggregate contribution to biodiversity of production lands, including paddock margins and bush remnants, under a range of alternative future management strategies.

Background

In New Zealand over 50% of land area is in agricultural or forestry production which forms the defining landscape matrix especially in lowlands. Indigenous biodversity is not restricted to formally protected areas, so a major contribution to New Zealand biodiversity conservation is effective conservation on production lands. Moreover, the proposed Global Plant Conservation Strategy within the Convention on Biological Diversity (CBD) includes a target of 30% of production lands being managed according to nature conservation principles by 2010. The operational research was centred on the Canterbury and East Cape regions. The two-research objectives accord with the approaches proposed for the CBD Global Strategy. Outputs are directed towards development of policy that will help the Ministry to discharge obligations primarily to the New Zealand Biodiversity Strategy (NZBS) and the proposed Ministerial Statement, and secondarily the Convention on Biological Diversity. A recent review for Ministry for the Environment (MfE) of indigenous biodiversity management in New Zealand production landscapes (Blaschke, P.M. Biodiversity-friendly farming and forestry: the biodiversity component of sustainable land management. Report to MfE, March 2002) described a considerable range of sometimes innovative "biodiversity-friendly farming and forestry" practices being carried out, principally under the auspices of regional councils and community-based "care" groups. However, these activities are ad hoc, rarely specifically address indigenous biodiversity goals, and are very variable in effectiveness. The current project should give such programmes better direction in the future.

Approach & Outcomes

Objective 1

This objective quantified native and non-native biodiversity on four farm sites, three in Canterbury and one in Tairawhiti. Protocols were developed and tested for the following aspects of biodiversity: bird populations on farmland, non-crop plant biodiversity, diversity of aerial beneficial insects. As well, functional agricultural biodiversity (FAB) was measured. This covered pest biological control potential and decomposition and mineralisation rates of soil organic matter.

Objective 2

This objective evaluated the actual and potential influence of production lands (as the dominant matrix across much of New Zealand) on the conservation and welfare of New Zealand biodiversity. It also modelled the aggregate contribution of production lands, including remnants and corridors, under a range of landscape design scenarios and developed alternative future strategies from which protocols for planning and management can be derived.

Outcomes:

The outcomes of this work are:

Objective 1

Developed protocols for the assessment of bird populations on farmland, non-crop plant biodiversity, pest biocontrol potential, assessment of organic matter decomposition rates and censuses of populations of beneficial insects. A further outcome is the adoption by New Zealand high schools of biodiversity assessment techniques as part of the school curriculum. These outcomes support New Zealand's participation in the CBD.

Objective 2

Produced a series of recommendations concerning landscape design and Biodiversity Friendly Farming and Forestry (BFFF) which are intended to help New Zealand discharge its commitment to the Global Plant Conservation Strategy within the CBD. Also, a novel analysis has been made available to the Ministry in which bird species diversity can be easily deduced from landscape diversity.

Summary

Goal: To quantify native and non-native biodiversity on farmland and assess associated ecosystem services provided; to analyse the contribution of production lands in future biodiversity policy scenarios. Context: The project gives tangible practical support to New Zealand's signing of the CBD. Methodology: This ranged from above-and below-ground assessments of biodiversity and its dynamics to modelling the contribution of production lands to biodiversity, including a Geographic Information Systems approach. Results: Gradients of biodiversity and ecosystem-service provision were detected from paddock margins to field centres. Also, a simple analysis was developed whereby bird species diversity could be estimated from landscape diversity. A series of recommendations concerning landscape design and BFFF was developed.

Publications

  1. Wratten, S.D. 2002. Biodiversity on Private Land: Worth the Bother? Cawthron Institute Annual Lecture, 2002. www.cawthron.org.nz
  2. Biodiversity on Farmland. Good Management Practices. Ministry for the Environment Report prepared by Lincoln University 2003.
  3. Biodiversity and Modified Landscapes 2003. A High School Resource Pack. Educational Solutions Ltd, PO Box 100, Lincoln, Canterbury.

4.3 FRM 222

Programme Title:

Small scale forest yield tables

Programme Leader:

Steve Croskery / Bill Liley

Institution:

Jaakko Poyry Consulting Ltd

Summary

The National Exotic Forest Description (NEFD) is New Zealand's official source of statistics on plantation forests. The NEFD is a partnership between industry and government, and annually surveys forest owners for age and area information about their forest crops. This information is aggregated and published each year. Periodically, it also publishes yield tables describing the growth and yield of these crops. Every five years or so, the area information, and the yield table information are brought together in the form of wood supply forecasts by region. Regional wood supply forecasts were most recently published in 2000. It is intended that this be repeated in 2006, subsequent to the revision of the current set of yield tables.

Background

Over the past two years there has been some concern expressed about the yield tables in terms of how well they describe the growth and yield of the non-corporate or small-grower resource. Some commentators are of the view that this resource is different to the corporate estate in terms of its management and yield, and may deserve separate yield tables.

This pilot study looks at five radiata NEFD croptypes, within three Wood Supply Regions. In each of two regions, two croptypes are considered and one in a third region. It compares the growth and yield of non-corporate crops with the related NEFD croptype yield table, compares some corporate yield data with the same NEFD croptype yield table, and the non-corporate yield with that of the corporate yield.

Approach & Outcomes

In terms of Total Recoverable Volume (TRV), there are some differences between the non-corporate yields and the NEFD yield table. There are also some differences between the corporate yields and the NEFD yield table, but not always between the non-corporate and corporate yield. This is summarised in the table below:

Wood Supply Region

Croptype

Non-Corporate Yield Different to NEFD Yield Table

Corporate Yield Different to NEFD Yield Table

Different to Each Other

         

Sthn Nth. Is.

ITWT

yes [considerably less]

yes [considerably less]

no

Sthn Nth. Is.

MTWT

yes [considerably less]

yes [considerably less]

no

Hawkes Bay

ITWT

no

yes [more]

yes

Hawkes Bay

ITPT

no

no

no

Otago-Southland

ITWT

no

yes [less]

yes

Note: IT stands for intensive tending and means pruned crops, MT or minimum tending means unpruned crops, WT means waste thinned, and PT means production thinned.

There is some suggestion and some support, mainly in the Southern North Island region, that compared to the NEFD yield tables the corporate estate produces more of its volume in the higher quality grades and less in pulp. Overall, however, there is not strong support for such a generalisation across the croptypes and regions.

The most compelling evidence from this investigation is that there is wide variation within croptypes, and within ownership groups, in both TRV and volume by log type. This is especially the case with pruned and pulplog types. Jaakko Pöyry Consulting has concluded that if there are to be improvements to the precision of yield description, then stratification of the resource should not be related to ownership type but instead to distinctions in site quality and silvicultural management.

An expansion of the current four radiata crop types and yield tables per Wood Supply Region is recommended. The classification could instead be based on:

  • Thinning Type;
  • Final Crop Stocking;
  • Site Quality;
  • Pruned Height;
  • Pruned Stocking.

This could result in up to 126 croptypes and yield tables per region, and will be more demanding in terms of area age reporting for the forest owners. However, this approach is seen as a significant improvement in terms of national yield description, with benefits for the outputs and applications of the NEFD reports.

Jaakko Pöyry Consulting has not considered broadening the range of log types represented in the yield tables, although this is not seen as posing any particular problem in the revision of the yield tables. A more detailed set of log types would likely be of use in applying the NEFD data to the planning of future wood processing initiatives.

4.4 FRM 223

Programme Title:

Poultry welfare indicators

Programme Leader:

Lindsay Matthews

Institution:

AgResearch CRI

Background

Report on Milestone (30 June 2003 - the overall project is planned over 3 years). Liaise with Bristol University and industry representatives to complete development of welfare assessment protocols for:

  1. mortality;
  2. leg health;
  3. skin and foot disorders; and
  4. (catching damage and dead-on-arrival (DOA).

Approach & Outcomes

This has been completed. Attended an international Broiler conference in Bristol in May and also visited Bristol University colleagues working on a related project in the UK. These discussions were invaluable in ensuring that the protocols to be used in the NZ and UK projects are scientifically valid and internationally acceptable. Details of protocols that were discussed included: scoring of skin and foot lesions; size and age of bruises, size and age of scratches and details of experimental design (e.g. sample sizes). For gait scoring about 200-250 birds per shed is required, for other measures about 100 birds is required).

Milestone 3

Collation and analysis of field tests (data collected by industry personnel/AgResearch staff) of standardised protocols for:

  1. mortality;
  2. leg health;
  3. skin and foot disorders; and
  4. catching damage and dead-on-arrival (DOA).

The protocols have been decided (summary below), with training in gait scoring still to take place (see Leg Health below), and there is likely to be some fine tuning of the detail of the protocols.

The summary of the protocols is:

Mortality

A booklet containing list of common pathologies/causes of death, detailed descriptions and colour photographs has been completed and has been made available to all personnel undertaking post-mortem analyses.

Leg health

Tube protocol for leg health will be the 5 point gait scoring system used by Bristol University. The training of the researchers and industry personnel in gait scoring is still to take place. The trainer (Dr Andrew Butterworth from School of Veterinary Science at the University of Bristol) has been unavailable due to teaching commitments but has agreed to visit NZ to undertake a gait scoring training course at AgResearch and nearby broiler sheds in mid October 2003. Currently, only the Bristol group are suitably qualified to undertake such training. This course will be similar to those currently running in the United Kingdom where Bristol staff have trained industry veterinarians as assessors of leg health by way of gait scoring. It is anticipated that the course will be attended by about 20 New Zealand researchers and industry personnel.

Foot burn

100 feet will be collected from each flock at slaughter (50 right feet and 50 left feet). The feet will be examined in the lab, and each foot will be given a score of 1 to 5 according to the foot burn chart.

Hock Burn

Approximately 100 birds will be examined on the line hock burn. The hocks will be given a score of 1 to 5 according to the hock burn chart.

Breast burn (blisters)

Approximately 100 birds will be examined on the line breast burn. Breast burns will be given a score of 0 = no breast blisters, 1 = 1 breast burn greater than 5 cents, 2 = 2 or more breast burns greater than 5 pence

Back Scratches

Approximately 100 birds will be examined on the line for back scratches. Back scratches are scored when they are longer than 2.5cm (there is no account of age or depth of scratch)

The scratches are scored as 0 = no scratches; 1 = 1 to 2 scratches; 2 = more than 2 scratches.

Bruising

Approximately 100 birds will be examined on the line for breast bruising. Breast bruises are scored only on the breast (not wings) as 0 = no bruises; 1 = 1 bruise greater than 50 cents; 2 = 2 or more bruises greater than 50 cents (age of bruise will be noted, i.e. old (green) or new (red)).

There continue to be some difficulties (due to conflicting work requirements of industry personnel) in arranging planning meetings that all key participants can attend.

4.5 FRM 224

Programme Title:

Beech Forest Health

Programme Leader:

Gordon Hosking

Institution:

Hosking Forestry (Forest Health Consultants)

Summary

To undertake a final assessment of the forest health plots established in association with Granville Operational Trials of beech management through small coupe harvesting, and report on the final results of the study.

Background

Disturbance of any kind in beech forest is often associated with residual tree mortality from native pinhole borers and pathogens. Small coupe harvesting inevitably involves such disturbance and some damage to edge trees, and carries the risk of mortality of coupe edge trees. A study to monitor any such impacts was considered an essential component of the harvesting trials.

Approach & Outcomes

Simple assessment plots designed by the author and trialed in the monitoring of residual tree decline following windthrow in the Kaimanawa Ranges, was considered well suited to the study. Circular plots of 3m radius centred on a single tree were established in undisturbed forest between the coupes, and on the edge of two sides of each coupe. A total of 18 coupe edge plots and 17 plots in undisturbed forest were established and their health formally assessed annually from 1994 to 1997, and in 1999 and 2003.

Outcomes:

Of the 292 trees included in the monitoring plots (including 122 hard beech, 95 Quintinia, and 68 kamahi) only 41 showed any evidence of ill health in the course of the study. Ill health peaked between 1996 and 1999, with most trees recovering by 2003. Almost all ill health was associated with wind damage, mainly on the coupe edges, but two plots within undisturbed forest were also affected. The native pinhole borers of the genus Platypus were almost always associated with serious decline in individual trees. As expected the peak of this damage occurred within 5 years of initial disturbance. Hard beech, the species of primary interest in the harvesting operation, was most affected, while kamahi was the least. The study showed small coupe harvesting trials, as carried out at Granville Forest, resulted in a small and temporary decline in tree health, consistent with a small localised disturbance event in a southern beech forest. No long term impacts were identified on the residual forest, and none is expected.

Summary:

A study to determine the impact on the health of residual forest resulting from small coupe harvesting in hard beech forest was undertaken in Granville Forest. Impact on coupe edge trees was compared with that in undisturbed forest between coupes, using circular tree centred plot assessed over a 10 year period.

The study showed small coupe harvesting as carried out in Granville Forest had little long-term impact on the forest, and what decline did occur, was caused mainly by native pinhole borers associated with localised windthrow. Tree ill health peaked 3 to 5 years after harvest, and had largely returned to good health 10 years post operation.

4.6 FRM 225

Programme Title:

Welfare impact of vertebrate poisons (Phase 2)

Programme Leader:

Cheryl O'Connor

Institution:

Landcare Research CRI

Summary

To assess the relative humaneness of vertebrate pest control poisons.

Background

To meet our goal of developing and using more humane vertebrate poisons, we need to assess the relative humaneness of poisons using a standardised method. The guidelines we developed in Objective 1 (2001/02) described the essential behavioural, physiological and pathological measures required to assess the welfare impact of vertebrate poisons. The guidelines also recommended that the relative humaneness of poisons should be assessed by comparing the type, severity and duration of welfare compromise caused by the main effects of each poison. This project therefore aims to use these guidelines to assess the relative humaneness of the possum poisons currently used in New Zealand.

Approach & Outcomes

Previous research (FRST C09X0009) provided data on the main behavioural, physiological and pathological effects for all possum poisons used in New Zealand. We used these data and applied the process developed in Objective 1 to rank the currently used possum poisons. The guidelines (Littin & O'Connor 2002) describe a five-step process that considers the type, intensity and duration of the main unpleasant effects to then make an assessment of the degree of welfare compromise caused by each effect. If the principles of the degree of welfare compromise provided in the guidelines (Step 4) are accepted, these data can be used to conduct the fifth step - to compare the type, degree and duration of welfare compromise between possum poisons. This will provide a full assessment of the relative humaneness of current possum poisons.

In addition, this data set provides the opportunity to refine the humane end-points used in toxicity and efficacy testing on possums. These data describe the course of key behavioural effects over time, which can then be related to the time and certainty of death, following such observations.

Outcomes:

In summary, cyanide caused mild abnormal breathing in 52% of the poisoned possums and convulsions occurred in all animals after they had become unconscious. For 1080 there is potential welfare compromise for 9.5 h following poisoning. A small percentage of possums poisoned with 1080 had minor to moderate retching, most became incoordinated and then all had mild to moderate tremors or spasms. The main welfare concern with phosphorus is the congestion of the gastric mucosa, which was linked to the adoption of a crouching posture. This was probably associated with some mild pain and lasted for 10 h until possums became prostrate. Cholecalciferol caused mineralisation in the organs of 67% of possums and lung damage in 59% of the animals. Seventy-one percent of possums had abnormal breathing for 1.5 days before death. They did not eat for 7 days, on average, and 21% lost more than 30% of their bodyweight. Finally, brodifacoum caused widespread haemorrhages of varying severity in all animals. The welfare consequences depend on the site and severity of the haemorrhages, which makes it difficult to generalise the welfare impact of this poison. Nevertheless, all animals had at least one severe haemorrhage in an area that would cause or contribute to pain, distress or weakness.

In addition, in order to describe a refined humane end-point for efficacy testing, we determined that the behaviour shown by most possums across all poisons was a prolonged period of prostration or lying, on the side, back or belly. We have defined prolonged in this case as a continuous 2 h or more. If this refined end-point, prolonged period of prostration, had been used there would have been a significant reduction, of several hours, in the period of suffering for many animals tested.

Summary:

As with many animal welfare assessments these recommendations are based on our "scientifically informed best judgement". We believe cyanide is the most humane poison for possums and would encourage its use, particularly encapsulated cyanide. 1080 seems acceptable at present, and phosphorus and cholecalciferol could be used with adequate justification. On humaneness grounds, there should be an extremely good practical reason before brodifacoum is used.

4.7 FRM 226

Programme Title:

Quantify contamination of groundwater

Programme Leader:

Murray Close

Institution:

ESR CRI

Summary

Transmission pathways of pathogens from domestic livestock to water. Quantify contamination of groundwater.

Background

This research programme is an integrated part of a much larger consortium - based programme (of 13 research projects) which aims to quantify the relative significance of key pathogen transmission routes from animals to water bodies. These projects together are also aimed at identifying effective mitigation measures and developing management guidelines, which help reduce faecal contamination of water bodies. This project is being undertaken to quantify microbial contamination of groundwater from dairying under border-strip irrigation.

Approach & Outcomes

This project is being undertaken to quantify microbial contamination of groundwater from dairying under border-strip irrigation. This is the type of irrigation most likely to cause leaching of microbes to groundwater but there have been no previous studies that have quantified contamination from this source. Microbial contamination of rural groundwater mainly occurs from 3 major sources: (1) landuse effects with leaching of microbes through the soil; (2) septic tank systems; and (3) poor wellhead protection with contamination directly entering via the well. Most surveys do not distinguish between the different sources of contamination.

Approach:

Groundwater contamination in the catchment was quantified by monitoring 6 wells at monthly intervals during the irrigation season. The wells were selected to avoid possible contamination from septic tanks and to ensure good wellhead protection. Well samples were analysed for E. coli, total coliforms, and Campylobacter. E. coli and total coliforms were analysed quantitatively using Colilert. Campylobacter was quantitatively analysed using a MPN/PCR format for C. jejuni and C. coli, these are the 2 major pathogenic species. A 3 tube MPN format was used, with volumes of 1000 ml, 500 ml, and 100 ml. This gave a quantification range of < 0.6 to >3.1 MPN per L. Irrigation and stocking information were collected from the individual farmers. Samples of cow faecal material (composites of 5 animals each time) have been collected from the dairy herd on each property on every second sampling occasion. These samples have been analysed for the presence of Campylobacter.

Outcomes:

There have been 7 sampling rounds, starting in October 2002, giving a total of 42 samples. All the wells have had total coliforms detected on all sampling occasions at levels ranging from 14 to >2,400 MPN/100ml. All wells have had E. coli detected on at least one sampling occasion, with the levels ranging from <1 to 120 MPN/100 ml. The mean level of E. coli in the well samples ranged from 12 to 36 MPN/100 ml. The drinking water standard for E. coli is <1 MPN/100 ml. The overall detection rate for all samples for E. coli is 83%.

Campylobacter have been detected in 5 out of the 6 wells on at least one sampling occasion with levels ranging from 0.6 to >3.1 MPN/L. There have been 6 samples out of a total of 42 with positive detections of Campylobacter, giving an overall detection rate of 14%. Half of the detections have been C. jejuni and the other half have been thermophillic Campylobacter but probably not C. jejuni or C. coli.

There is a very good correlation between Campylobacter and E. coli (r=0.52, p=0.001, n=36) but not between Campylobacter and total coliforms (r=0.03, p=0.87, n=36). However, there are still relatively few number (6) positive Campylobacter results with which to establish this correlation, and it may change slightly as further data are collected.

Three composite samples of cow faecal material (each composites of 5 cow pats) have been collected on each sampling occasion from half the sites, with the other half of the sites being sampling in the following sampling round. All but two of the faecal samples (19/21 samples) have been positive for C. jejuni.

The irrigation and stocking information has been collected from most of the farmers but 1-2 still need to be followed up to get the most recent data.

Summary:

The goal of this project was to quantify microbial contamination of groundwater under dairying with border strip irrigation. Six wells were selected in the Waikakahi catchment, South Canterbury, and sampled monthly during the irrigation season. The samples were analysed for total coliforms, E. coli and Campylobacter.

The results indicate that both the indicator and pathogen bacteria, Campylobacter, are being detected in the groundwater, with the indicator bacteria being detected at much higher levels as would be expected. The selection of the wells to avoid septic tank contamination and wellhead protection issues means that the microbial contamination would be coming from dairying combined with border strip irrigation. There is a good correlation between Campylobacter and E. coli but the level of this correlation may change slightly as further data are collected.

Publications

  • Close, M.E.; Savill, M. 2003. Transmission pathways of pathogens from domestic livestock to water - Quantify contamination of groundwater. ESR Client Report CSC0302. A report for MAF Policy. 13 p.

4.8 FRM 227

Programme Title:

Management guidelines for indigenous forests

Programme Leader:

Rob Allen

Institution:

Landcare Research CRI

Summary

Developing management guidelines for the sustainable management of indigenous forests on private land

Background

Assessing landscapes to develop silvicultural systems, consistent with the principles of ecosystem management, which allow high-value timber production from indigenous species under the Forests Act and so support rural communities and development.

Approach & Outcomes

Indigenous forest managers are faced with managing for multiple goals, such as maintaining species composition, ensuring regeneration and appropriate yield regulation. Therefore, silvicultural systems are needed that work in harmony with natural variation in tree growth and forest structure, including regeneration, and species composition. Such systems require techniques for assessing landscapes from an ecological perspective and using these to design effective silvicultural systems that minimise environmental impacts. Ecological site classification is widely used to delineate parts of the landscape that should be subjected to similar management.

Approach:

Increasing areas of mixed beech forests dominated by the light-demanding red beech and the more shade tolerant silver beech are being covered under plans and permits on individual properties approved under the Forests Act. As a consequence, we demonstrate how multifaceted ecological information can be collected in red-silver beech forest and used by forest owners to underpin silvicultural systems that take account of variation in structure, composition and growth. This involved:

  • undertaking field sampling in a 300 ha area of red-silver beech forest in the Maruia Valley to represent the scale faced by most indigenous forest managers;
  • determining which factors relate to variation in individual tree growth and forest structure, including regeneration, and species composition, in so far as they are relevant to forest management; and
  • evaluating whether a common set of factors relate to variation in structure, composition and growth among species within the same forest and between different types of forest.

This work essentially evaluates the utility of an ecological site classification of individual stands at a property scale.

Outcomes:

  • overall our analyses showed that <25% of the plot-level variation in regeneration, forest structure, and individual tree growth could be predicted directly or indirectly by our measured site, stand and soil variables; and
  • in contrast, within-plot variables appeared much more important in influencing individual tree growth. Our multilevel regression models of individual tree growth showed that >85% of the variation in tree growth that could be explained was explained by within-plot effects.

Recommendations:

Because this report emphasises that variability in tree growth, forest structure, and species composition is poorly explained by plot-level site, stand and soil variables we recommend further research should in part focus on within-stand processes. The following projects would make useful additions:

  • develop a clearer understanding of how local processes control tree growth;
  • develop a clearer understanding of how local processes control forest biodiversity;
  • contrast the influence of competitive suppression on trees with competitive release; and
  • conduct long-term studies of processes influencing structure, growth and composition that include experimental manipulations.

Summary:

Assessing landscapes to develop site-specific silvicultural systems is required under the Forests Act to allow high-value timber production from indigenous species. Increasing areas of mixed beech forests dominated by the light-demanding red beech and the more shade-tolerant silver beech are being covered under Forests Act plans and permits. We demonstrate how multifaceted ecological information can be collected in a red-silver beech forest and used by forest owners to underpin silvicultural systems that take account of variation in structure, composition and growth. Overall our analyses showed that <25% of the plot-level variation in regeneration, forest structure, and individual tree growth could be predicted directly or indirectly by our measured site, stand and soil variables. In contrast, within-plot variables appeared much more important in influencing individual tree growth. Our multilevel regression models of individual tree growth showed that >85% of the variation in tree growth that could be explained was explained by within-plot effects. Because this report emphasises that variability is poorly explained by plot-level variables, we recommend further research should in part focus on within-stand processes.

Publications

  • Allen, R.B.; Wiser, S.K.; Coomes, D.A.; Peltzer, D. 2003: Stability and growth of residual trees following disturbance. In: Proceedings of Joint Australian and New Zealand Institute of Forestry conference, Queenstown. P. 441.

4.9 FRM 228

Programme Title:

Low impact silviculture

Programme Leader:

Susan Wiser

Institution:

Landcare Research CRI

Summary

Low-impact ecosilviculture.

Background

Growth and mortality of residual trees after small-coupe harvesting were analysed for indigenous timber production in South Island beech (Nothofagus) forest.

Approach & Outcomes

Context of the project:

Between 1993 and 2001 New Zealand imports of timber products increased by 80% to $1200 million. Hidden within this is the 220% increase in high-value timber imports over this time. Much of this timber comes from non-sustainably managed sources in Malaysia, Fiji, etc. Over a similar time period `mill door' prices of indigenous high-value timbers have increased by about 200% bringing them in line with international prices. There is thus economic, environmental and social imperatives for New Zealand to develop an indigenous forest industry based on careful management of a portion of its 1.5 million ha of privately owned indigenous forest. Existing forests, rather than slow-growing indigenous plantations, provide the only opportunity for an economically significant industry over the next half-century. The major constraint to harvesting timber from existing forests is in meeting societal expectations for sustainable management. The pressure is for forest ecosystem sustainability, which means retaining the structural, compositional, and functional characteristics of these forests. An essential part of achieving this requires an understanding of how harvesting canopy trees impacts on the health, structure, and composition of residual trees.

Approach:

To examine the growth and survival of residual trees after disturbance we:

  • briefly review and present relevant examples from the literature
  • present a detailed analysis of data collected over the last 7-9 years from a series of small coupe (<0.2 ha) harvesting trials in beech forest.

This involved:

  • remeasuring existing small-coupe trials at Granville Forest;
  • analysing tree growth and mortality data from three localities: Granville Forest (hard beech forest), Station Creek (red-silver beech forest) and Glenhope (red-silver and hard beech forests).

Outcomes:

Based on individual tree growth analyses it is clear that species, harvesting proximity and individual tree size can all relate to the level of growth response upon removal of neighbours. On average silver beech trees grew four times faster following harvesting of adjacent trees whereas red beech trees showed no overall change in growth. It was somewhat surprising that across all species, trees on the edge of coupes that were attacked by Platypus did not grow more slowly than trees that were not attacked; in fact trees that were able to repel the attack by occlusion were relatively fast growing.

Several factors were shown to influence the mortality rates of trees on the edge of coupes. For red, silver and hard beech a key determinant of tree mortality is Platypus attack and this attack is pronounced on trees damaged during harvesting. In combination with our edge tree growth analyses, this suggests that faster growing trees are more likely to survive Platypus attack. It follows that repelling Platypus attack by occlusion, as well as tree size and species are also related to tree mortality.

Major Conclusions

  • Much can be learned about compensatory growth and mortality from unmanaged forests. Silver and red beech show similar growth responses in canopy trees following harvesting to those found following natural disturbance (e.g., earthquake).
  • Compensatory growth and mortality following timber harvesting have important implications for selecting individuals to harvest.
  • The suite of factors explaining compensatory growth and mortality can be used to provide a framework for forest management. For example, we would expect the nature of compensatory growth to shift in predictable ways along various stress gradients.
  • At a forest (or property) level the impacts of harvesting on growth and mortality need to be better incorporated into growth predictions and yield regulation.

Recommendations

Further development of our understanding of compensatory growth and mortality is required to underpin sustainability requirements in management plans developed under the Forests Act. The following projects would make useful additions to this report:

  • Continue the remeasurement of low-impact harvesting trials in beech forest.
  • Establish additional low-impact harvesting trials in other types of forest.
  • Further characterise compensatory growth and mortality of other tree species following disturbance by analysing existing data.
  • Develop a general framework for compensatory growth and mortality.
  • Demonstrate how compensatory growth and mortality can be included in management plans and yield regulation.

Summary:

Growth and mortality of residual trees after small-coupe harvesting are presented for South Island beech (Nothofagus) forest. The major constraint to harvesting timber from existing forests is in meeting societal expectations for sustainable management that in part means retaining the structural, compositional, and functional characteristics of these forests. This involved remeasuring existing small-coupe trials at Granville Forest and analysing tree growth and mortality data from three localities: Granville Forest (hard beech forest), Station Creek (red-silver beech forest) and Glenhope (red-silver and hard beech forests). Based on individual tree growth analyses it is clear that species, harvesting proximity and individual tree size can all relate to the level of growth response upon removal of neighbours. Several factors were shown to influence tree mortality on the edge of coupes with Platypus attack being a key and this attack pronounced on trees damaged during harvesting. The impacts of harvesting on growth and mortality need to be better incorporated into growth predictions and yield regulation in management plans.

Publications

  • Allen, R.B.; Wiser, S.K.; Coomes, D.A.; Peltzer, D. 2003: Stability and growth of residual trees following disturbance. In: Proceedings of Joint Australian and New Zealand Institute of Forestry conference, Queenstown. P. 441.

4.10 FRM 229

Programme Title:

Pinhole borer guidlines

Programme Leader:

Eckehard Brockerhoff

Institution:

Forest Research CRI

Summary

To provide to MAF conclusive management guidelines for minimising the incidence and effects of pinhole borer following harvesting, to underpin policy advice on Part IIIa of the Forests Act.

Background

The sustainable management of New Zealand's beech forests requires attention to the native pinhole borer beetles, Platypus spp. Harvesting or natural forest disturbance can lead to outbreaks of these beetles, which may result in mortality of healthy beech trees. To avoid such outbreaks, management prescriptions recommend the cutting of harvesting slash into 1-m pieces and the treatment of stumps with urea. This is thought to accelerate drying or decomposition processes, which would reduce the survival of pinhole borer brood. However, under the current forest management system of small harvest gaps that is now commonly practised, the effectiveness of slash and stump treatments has not been assessed. Furthermore, little information is available on the potential impact of pinhole borer in these conditions. These are important issues for the sustainable management of beech forests, especially those under private ownership where harvesting occurs.

Approach & Outcomes

Approach

The incidence of pinhole borer attack in treated and untreated slash and stumps was monitored since November 1998 in eight experimental plots established shortly after harvesting of beech trees in small gaps (mean gap size ca. 0.04 ha) at Station Creek, Maruia Valley, north Westland. To obtain more detailed data on the breeding success and phenology of pinhole borer, emergence traps were installed over individual borer holes on treated and untreated slash and stumps. To assess the potential impact of harvesting on the health of the remaining forest, trees around the coupe edges and in control plots were monitored. The data were also used to estimate the compartment-wide mortality of beech trees. Mortality data were compared with equivalent data in an adjacent compartment where no harvesting had occurred, and where trees had been similarly marked in 1998.

Outcomes

Following harvesting in late 1998, there was a heavy attack by pinhole borer of nearly all slash sections and stumps. During the first two years, cutting slash and treating stumps did not result in reduced attack or reduced survival of pinhole borer. By mid-2002, there was neither an effect on moisture content or decay of slash, nor on the emergence of beetles. Although the number of tunnels producing boring dust was lower in treated than in untreated slash in 2000/2001 and 2001/2002, this did not result in a decrease in pinhole borer emergence in the following years. Many new attacks had occurred in 2000/2001 and 2001/2002, coinciding with the emergence of beetles from this slash, but the number of active tunnels (i.e., tunnels producing boring dust) was greatly reduced in 2002/03. However, even in the fifth year after harvesting a considerable number of beetles emerged from this slash (about 17% of the total), demonstrating the long-term nature of these attacks. Thus there remains the potential for build-up of populations and further attack of healthy trees.

There was notable mortality of edge trees and of trees in adjacent control plots, where five trees over 40 cm dbh died apparently as a result of pinhole borer attack. Overall mortality was similar with 6.1% of the monitored edge trees and about 5.6% of trees in control plots in the five years since harvesting, which effectively lead to considerable enlargement of some gaps. Extrapolated to the entire compartment, the observed mortality was about 17.2 trees per ha, which was lower than that assumed by a stand model for this forest (22.4 trees per ha). Mortality and attack rates in the compartment where harvesting occurred considerably exceeded that in an adjacent, undisturbed compartment (1.8% mortality), but it is not clear whether this difference can be attributed to the harvesting disturbance.

  • The slash and stump treatments have not yet shown any noticeable benefits, and it appears that longer-term effects are not likely to occur. These results suggest that cutting slash in short pieces and treating stumps with urea are not effective in small gaps of about 0.04 ha created by group-selection harvesting (although it is conceivable that such treatments could be more effective in large-scale clearfells with a different microclimate, where accelerated drying of cut slash may result). However, the study shows that substantial attack of slash and stumps can occur and that there is a risk of attack and mortality of edge trees when large amounts of slash are available for breeding of pinhole borer. This could indeed lead to beetle outbreaks, especially in this forest management system where harvesting is likely to be carried out every few years in a given area. Thus we recommend to consider the following alternative management options for small gaps:
  • Harvesting could be carried out in stages with a reduced initial harvesting rate to accommodate potential subsequent tree mortality. If mortality occurs, this could then be subsumed in later harvests by selectively removing trees that are dying or have just died, thereby reducing unwanted tree losses. This would have a further benefit in that slash from dying trees would be greatly reduced and not become available for beetle breeding, potentially reducing the population build-up.

· Other, preventative control methods could be considered to prevent damage from pinhole borer, particularly in areas where there is a high risk of attack because of a large proportion of senescent trees such as in the Maruia Valley:

  1. Special attention should be given to stumps because more beetles emerged from these than from slash. We propose that stumps be cut as low to the ground as possible to reduce the amount of material available for pinhole borer breeding.
  2. To enable a response to any outbreaks of pinhole borer that could potentially lead to dieback in the remaining forest, it is critical to monitor the development of pinhole borer populations after harvesting, for example by surveying attack rates of slash and edge trees and mortality caused by pinhole borer.

Recommendations for further research

  • It would be of interest to re-examine the tagged trees in the study area perhaps over the next five to ten years to gain a better understanding of the long-term dynamics of pinhole borer attacks. This is relatively simple and would not necessarily have to be done on an annual basis.
  • The development of improved methods for monitoring pinhole borer populations would be desirable in order to recognise outbreaks early on so that appropriate management actions could be undertaken. The identification of beetle aggregation pheromones would greatly assist the development of an efficient monitoring system.

Summary

This study examined the effects of slash and stump treatments that are thought to reduce the risk of damage from pinhole borer beetles following selection harvesting of beech. For five years following harvesting in north Westland, treated and untreated slash and stumps were monitored for pinhole borer attack, emergence of beetles and wood conditions. To assess the potential impact of harvesting on the health of the remaining forest, trees around the coupe edges and in control plots were monitored, and the compartment-wide mortality was estimated.

Treatments had no great effect on moisture content or decay of slash, and by mid-2003 beetle emergence did not differ significantly between treated and untreated slash. However, the heavy and continuing attack of slash shows that on-going problems with pinhole borer are possible under this harvesting regime. This could lead to increasing attack of healthy trees, and this appears to have already occurred to some extent. Cutting slash and treating stumps with urea have not proven effective in reducing pinhole borer problems. However, it is clear that cutting stumps as low to the ground as possible will contribute to reducing the build-up of pinhole borer populations. Alternative harvesting regimes could be considered to subsume some tree mortality in harvesting schedules. Monitoring the development of populations is recommended to enable a response to pinhole borer outbreaks that could potentially lead to dieback in the remaining forest.

4.11 FRM 231

Programme Title:

Rodeo calf roping

Programme Leader:

Mark Fisher

Institution:

Kotare Consultants

Summary

To determine if there are any adverse effects on the welfare of calves roped during a rodeo.

Background

Rodeo calf roping involves the catching of the calf by a lasso thrown by a rider on horseback. The calf is brought to a fairly abrupt halt once it reaches the end of the rope, and is then thrown to the ground and tied by the rider. There is little scientific information on the effects of roping on calf welfare. The National Animal Welfare Advisory Committee (NAWAC) requested such information, in a New Zealand context, to assist with the formulation of the Code of Welfare for rodeo animals.

Approach & Outcomes

Approach:

Competition (n = 14) and Control (n = 8) dairy-beef calves were studied at the Raetihi rodeo (15 & 16 March 2003). The calf roping event was divided into two sections on each day, with the same Competition calves used in both, but half the entrants competing at each time. Behavioural observations were undertaken in the period up to 30 minutes immediately after roping. Blood samples were taken before, after and 24 hours after roping, and the plasma analysed for the enzymes creatine kinase and lacatate dehydrogenase (to assess muscle or tissue damage) and the hormone cortisol (to assess stress).

Outcomes:

In the two calf-roping events (one on each day) 51% and 44% of the calves were successfully caught and tied by the competitors. The winning times for each event were 12.39 and 12.56 seconds respectively, and the average time was 19.14 seconds (range 10.55 to 43.90 seconds).

No calves were injured during the rodeo, though one appeared to be have been roped awkwardly around the throat region. This possibly caused the, dizziness and disorientation evident when the calf was released, but the animal recovered quickly.

Immediately after being released, nearly all roped calves got to their feet and ran, or walked then ran to the exhaust pen gate. Once in the exhaust pen, most calves settled quickly (within 20 seconds) with no difference between those calves caught and those not caught. Most activity was confined to looking around, walking, or standing still often with heads down. The behavioural repertoire during this time also included occasional instances of grooming, tail flicking, urinating, defaecating, sniffing, and licking. There were no significant behavioural changes in the calves attributable to having been roped except for a short period of head-shaking and sham-chewing in some of the calves. This was noted in approximately a third of the roped calves and perhaps reflected an attempt to clear arena dirt from the mouth.

Analysis of plasma samples demonstrated that there were statistically significant increases in creatine kinase and lactate dehydrogenase enzymes due to both being in the competition and being roped. Mean (and range) creatine kinase concentrations were 1117.9 (557-2162) U/l after roping, and 711.5 (354-1157) U/l 24 hours after roping, compared with 368.5 (265-547) in the Control calves during these times. Similarly, lactic dehydrogenase concentrations were 1073.2 (895 - 1275) U/l immediately after roping and 1062.8 (873 - 1276) U/l at 24 hours, compared with 996.3 (857 - 1106) U/l in the Control calves. As the magnitude of these increases was small, it is suggested they may have been due to the physical exercise more than muscle injury. An increase was detected in the hormone cortisol, where concentrations averaged 84.2 (33 - 113) nmoles/l after roping, and 125.1 (58 - 156) nmoles/l 24 hours after roping, compared with 64.9 (22 - 109) in the Control calves. While roping, throwing and tying significantly affected cortisol concentrations, their magnitude again suggests that it was not severe.

Collectively, the results indicate that roping is not adversely affecting the short-term welfare of this class of calves.

Summary:

Calves were monitored at a New Zealand rodeo to determine if their welfare was adversely affected by being roped, thrown and tied. Calves settled quickly after the event, regardless of whether or not they had been successfully caught. There were no behavioural changes attributable to roping except for a short-lived period of chewing and head shaking in some calves. Analysis of blood samples revealed significant changes in hormone and enzyme concentrations. However, these changes were not of a magnitude indicative of significant injury or muscle damage.

Publications

A scientific paper is being prepared for submission to the New Zealand Veterinary Journal.

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Farm Monitoring Programme Manager
Monitoring and Evaluation
MAF Policy
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NEW ZEALAND
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