New Zealand Journal of Forestry Science最新文献

{"title":"Logging damage to residual trees during sustainable harvesting of uneven-age stands in the Hyrcanian forests of Iran","authors":"A. I. Bodaghi, Mehrdad Nikooy, R. Naghdi, F. Tavankar","doi":"10.33494/nzjfs502020x15x","DOIUrl":"https://doi.org/10.33494/nzjfs502020x15x","url":null,"abstract":"Background: The frequency of wounded trees and intensity of wounds during logging operations can have serious impacts on stand growth and forest sustainability. The aims of the study were to evaluate and compare stand (tree and regeneration) damage level, wound characteristics, and damage types occurring when using a cable skidder in salvage logging and selection cutting. \u0000Methods: This study was conducted on four sites of mixed uneven-aged hardwood stands in the Hyrcanian forests of Iran. At two sites, salvage logging was applied (SL1 and SL2), and low-intensity selection cutting (SC1 and SC2) was applied at the other two. A systematic plot sampling design was used on the study area for damage assessment. \u0000Results: The percentage of regenerating trees damaged was 2.8, 2.1, 4.3, 1.4 %, in SL1, SL2, SC1, and SC2, respectively. The corresponding percentage of damaged trees was 4.3, 3.7, 4.9, 1.7 %. Most of the damage (48–79%) to the stand occurred during the winching stage at all the sites. Most of the wounds were located on the bole (51–78%). The average wound height and wound size at selection cutting sites were significantly higher than at the salvage logging sites. The incidence of high-intensity wounds at the salvage logging sites (55% at SL1 and 57% at SL2) was higher than at the selection cutting sites (24% in SC1 and 30% in SC2). Regenerating beech (Fagus orienalis Lipsky) and alder (Alnus subcordata C.A.Mey) had the highest incidence of damage. The number of damaged trees increased with increasing winching distance. \u0000Conclusion: Damage levels in stands during salvage logging and low-intensity selection cutting are lower (about a quarter) than the damage level to residual trees (12–23%) and regeneration (5–11%) from conventional selection cutting in uneven-aged mixed hardwood stands in the Hyrcanian forests. Because of the ecological and conservation value of deadwood, if the incidence of wind-fallen trees is low, the wood should be left in forest stands due to the high cost of salvage logging and the damage caused to residual and regenerating trees.","PeriodicalId":19172,"journal":{"name":"New Zealand Journal of Forestry Science","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2020-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45152167","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of land cover type on carabid beetles (Coleoptera: Carabidae) of the Canterbury foothills, New Zealand","authors":"L. Berndt, E. Brockerhoff","doi":"10.33494/nzjfs492019x54x","DOIUrl":"https://doi.org/10.33494/nzjfs492019x54x","url":null,"abstract":"Background: Land cover changes during the recent history of New Zealand have had a major impact on its largely endemic and iconic biodiversity. As in many other countries, large areas of native forest have been replaced by other land cover and are now in exotic pasture grassland or plantation forest. Ground beetles (Carabidae) are often used as ecological indicators, they provide ecosystem services such as pest control, and some species are endangered. However, few studies in New Zealand have assessed the habitat value for carabid beetles of natural forest, managed regenerating natural forest, pine plantation forest and pasture. \u0000Methods: We compared the carabid beetle assemblages of natural forest of Nothofagus solandri var solandri (also known as Fuscospora solandri or black beech), regenerating N. solandri forest managed for timber production, exotic pine plantation forest and exotic pasture, using pitfall traps. The study was conducted at Woodside Forest in the foothills of the Southern Alps, North Canterbury, New Zealand, close to an area where the critically endangered carabid Holcaspis brevicula was found. \u0000Results: A total of 1192 carabid individuals from 23 species were caught during the study. All but two species were native to New Zealand, with the exotic species present only in low numbers and one of these only in the pasture habitat. Carabid relative abundance and the number of species was highest in the pine plantation, where a total of 15 species were caught; however, rarefied species richness did not differ significantly between habitats. The sampled carabid beetle assemblages were similar across the three forested habitat types but differed significantly from the pasture assemblages based on unconstrained and canonical analyses of principal coordinates. Holcaspis brevicula was not detected in this area. \u0000Conclusions: Our results show that managed or exotic habitats may provide habitat to species-rich carabid assemblages although some native species occur only in natural, undisturbed vegetation. Nevertheless, it is important to acknowledge the potential contribution of these land uses and land cover types to the conservation of native biodiversity and to consider how these can be managed to maximise conservation opportunities.","PeriodicalId":19172,"journal":{"name":"New Zealand Journal of Forestry Science","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2019-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48242198","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Incorporating competition factors in a mixed-effect model with random effects of site quality for individual tree above-ground biomass growth of Pinus kesiya var. langbianensis","authors":"Mingchuan Nong, Yanbing Leng, Hui Xu, Chao Li, Guanglong Ou","doi":"10.33494/nzjfs492019x27x","DOIUrl":"https://doi.org/10.33494/nzjfs492019x27x","url":null,"abstract":"Background: Accurate biomass estimation has critical effects on quantifying carbon stocks and sequestration rates, and above-ground biomass (AGB) growth models are a key component of tree biomass estimation. The study objective was to develop a growth model for AGB of an individual tree by combining competition factors and site quality using a mixed-effect model. \u0000Methods: The AGB of 128 sampling trees was investigated for Simao pine (Pinus kesiya var. langbianensis) at three typical sites near Pu’er City of Yunnan Province, China. Richards’ Equation was used for the basic growth model (BM) of the AGB, and a mixed-effect model with random effect of site quality (MEM) based on BM and a mixed-effect model with fixed effect of competition factors (MEMC) based on MEM were built using S-plus. \u0000Results: Both mixed-effect models are significantly better than the basic model in fitting and predicting the individual tree AGB growth for Simao pine, but the MEM is better than the MEMC. Moreover, the mixed-effect model with competition factors and site quality is the optimal estimation model due to its highest prediction precision (P=86.08%) as well as the lowest absolute average relative error (RMA=54.34%) and average relative error (EE =6.45%). \u0000Conclusion: A model including site quality and competition factors can be used to improve the tree AGB growth estimation for the individual tree AGB growth of Simao pine.","PeriodicalId":19172,"journal":{"name":"New Zealand Journal of Forestry Science","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2019-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45878303","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Describing area and yield for small-scale plantation forests in Wairarapa region of New Zealand using RapidEye and LiDAR","authors":"Cong Xu, B. Manley, J. Morgenroth","doi":"10.33494/nzjfs492019x16x","DOIUrl":"https://doi.org/10.33494/nzjfs492019x16x","url":null,"abstract":"Background: New Zealand does not have a national forest inventory based on ground measurements. The National Exotic Forest Description (NEFD) is based on surveys of forest owners but lacks reliability in describing area and yield for small-scale forests, given that over half of the small-scale forests were not included in the direct NEFD survey. This has led to an insufficient understanding of the wood supply from these forests, which will raise problems as the majority of the small-scale forests are approaching maturity and are anticipated to contribute more than 40% of wood supply in the next decade. Therefore, having accurate estimation of this resources is critical for marketing, harvesting and logistic planning. Furthermore, the current NEFD does not incorporate a spatial representation. The aim of this study was to test the utility of remote sensing dataset for providing information on the area and yield of small-scale forest resources through a case study in the Wairarapa region of New Zealand. \u0000Methods: Classification and regression tree analysis was applied to both RapidEye and LiDAR datasets to map the net stocked area of small-scale plantation forests in Wairarapa. Results were compared against forest areas that have been determined from manual digitisation. For each forest, stand variables mean top height, basal area, volume and stand age were estimated using LiDAR-derived metrics. This allowed the development of maps for these stand variables. \u0000Results: The automatically mapped plantation area was 4.2% (1 614 ha) less than the reference area (i.e. manually digitised plantation area), together with manually digitised young plantations which were not detected from automated approach, the area differed only by -0.6% (235 ha) from the reference area. The yield tables developed using modelled stand variables were all within a realistic range and were comparable to wood availability forecast (WAF) yield tables, producing on average 27 m3 ha-1 less than the WAF yield. \u0000Conclusions: The mapping approach produced comparable results to the area calculated using manual digitisation. However, this approach struggles to detect young plantings due to the resolution of the remote sensing datasets used; hence manual digitisation is required to map the young plantations that were within 3–5 years of planting. This study also confirmed that the remote sensing approach could be used to describe forest yield, although the approach failed to predict the full range of ages of the mapped forest resource. The estimation of plantation age could be improved by including plot data with a wider range of stand ages or investigating different models for age estimation. It is also possible to review time-series satellite imagery to detect establishment periods for the forests.","PeriodicalId":19172,"journal":{"name":"New Zealand Journal of Forestry Science","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2019-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47087120","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparison of cost, productivity and residue yield of cut-to-length and fuel-adapted harvesting in a Pinus radiata D.Don final harvest in Western Australia","authors":"M. Strandgard, R. Mitchell","doi":"10.33494/nzjfs492019x37x","DOIUrl":"https://doi.org/10.33494/nzjfs492019x37x","url":null,"abstract":"Background: Forest biomass is a major global source of biofuel. To compete with other energy sources its delivered costs need to be reduced. Globally, logging residue (LR) is likely to be the cheapest, readily available forest biomass form. LR transport is a major cost component. \u0000Methods: A harvester-forwarder harvest system was studied in two adjacent areas to compare Swedish “fuel-adapted harvesting” with conventional cut-to-length harvesting at the stump in a mature Pinus radiata D.Don plantation in Western Australia to assess the impact of fuel-adapted harvesting on costs and productivity of a harvester and forwarder producing logs and extracting LR and on LR yield. \u0000Results: Harvester and forwarder productivities producing logs were significantly reduced in the fuel-adapted area compared with the conventional area which increased log production costs for the fuel-adapted site by 15%. Forwarder productivity extracting LR and LR yield were significantly greater in the fuel-adapted area which reduced LR extraction costs by approximately 28%. This was due to the ease of loading LR from residue piles created during fuel-adapted harvesting compared with loading scattered residue from conventional harvesting. \u0000The cost reduction for LR extraction from the fuel-adapted area exceeded the increased log harvest and extraction costs. This resulted in the combined log and LR costs for the fuel-adapted area being approximately 12% lower than those for the conventional area. Increased forwarder productivity through adoption of larger load bunks and residue-specific grapples combined with increased operator experience with fuel-adapted harvesting would be likely to further decrease log and LR production costs. \u0000Conclusions: The results show that adoption of fuel-adapted harvesting could reduce LR delivered costs, thus increasing its viability as a biofuel. However, primary transport cost is only one component of LR delivered costs and needs to be considered in combination with the reduction of other supply chain costs, particularly secondary transport costs which can make up a large proportion of LR delivered costs. Because removal of most LR from a site can reduce subsequent tree growth, guidelines specifying the proportion of LR retained should be considered.","PeriodicalId":19172,"journal":{"name":"New Zealand Journal of Forestry Science","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2019-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46932561","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Allometric biomass equations for young trees of four broadleaved species in Albania","authors":"Erion Istrefi, E. Toromani, N. Çollaku, B. Thaçi","doi":"10.33494/NZJFS492019X51X","DOIUrl":"https://doi.org/10.33494/NZJFS492019X51X","url":null,"abstract":"Background: Biomass assessment of young forest stands is important because of their role in the carbon cycling. The aim of this study was to develop biomass equations for young broadleaved species growing in natural conditions in Albania. \u0000Methods: Five forest stands were investigated using circular sample plots. Diameter at breast height (DBH) and height (H) from 58 sampled trees ranging in age from 4 to 34 years old of Turkey oak (Quercus cerris L.), sweet chestnut (Castanea sativa Mill.), European hornbeam (Carpinus betulus L.) and manna ash (Fraxinus ornus L.) were measured in situ. Logarithmic regression equations were used and tested for their performance to estimate aboveground and tree-components biomass for each species using DBH, H and their combination DBH2 x H as predictors. \u0000Results: We found that DBH was a reliable predictor for estimation of aboveground and components biomass for young trees but the inclusion of height in biomass allometry did not improve the biomass estimation. We observed differences in scale (?0) and exponent (?1) coefficients of biomass models, not only between broadleaved species, but also among tree-components within species. Both coefficients were strongly species-specific and their values reflect differences in biomass stocking rate due to different growth strategies of each species in early development phases. \u0000Conclusions: Allometric equations to estimate aboveground and tree-component biomass appeared to be species-specific, meaning that such models are applicable for species growing at sites with similar ecological conditions. From the tree variables used, DBH was the most reliable predictor of aboveground and individual components biomass, whereas height proved to be a promising predictor for stand biomass. These allometric equations developed for young trees will improve the accuracy of current estimates of forest carbon stock in Albania.","PeriodicalId":19172,"journal":{"name":"New Zealand Journal of Forestry Science","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2019-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47603767","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Soil mycobiota under managed and unmanaged forests of Nothofagus pumilio in Tierra del Fuego, Argentina","authors":"L. Elíades, M. Cabello, V. Pancotto, A. Moretto, Natalia A Ferreri, M. Saparrat, M. Barrera","doi":"10.33494/NZJFS492019X53X","DOIUrl":"https://doi.org/10.33494/NZJFS492019X53X","url":null,"abstract":"Background: Management practices can modify the productivity of forests and the associated microbial diversity of soil. The soil mycobiota is considered a key factor in the ecological functions of forests. Forests of Nothofagus pumilio (Poepp. & Endl.) Krasser (Nothofagaceae) are the main source of timber and one of the most important economic resources in the province of Tierra del Fuego (Argentina). However, there is no information on the impact of forest management interventions for the soil mycobiota, which can be reliable biological indicators of disturbance.Methods: Fungi were isolated from samples of soil collected under several Nothofagus pumilio forests subjected to different types of management and periods of time since the intervention. Types of management were represented by harvested forest with a shelter wood cutting, stockpile area and control forest without intervention and the periods of time since intervention were 1, 5–10 and 50 years. Species richness, evenness and Shannon’s diversity index of the mycobiota in each condition of management were calculated. Additionally, the effect of seasonality was analysed.Results: The soil mycobiota was represented by 70 taxa. Richness and/or Shannon’s diversity index of the mycobiota between undisturbed forest and stockpile area were higher in May (autumn) than in September or November. There were no differences in mycobiota diversity between dates in the harvested forest.Conclusions: Our results indicate that the forest intervention per se did not negatively affect the soil culturable mycobiota composition of N. pumilio forests in Tierra del Fuego (Argentina).","PeriodicalId":19172,"journal":{"name":"New Zealand Journal of Forestry Science","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2019-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41262526","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Opportunities and limitations of exotic Pinus radiata as a facilitative nurse for New Zealand indigenous forest restoration","authors":"Adam Forbes, D. Norton, F. Carswell","doi":"10.33494/NZJFS492019X45X","DOIUrl":"https://doi.org/10.33494/NZJFS492019X45X","url":null,"abstract":"Background: We investigated the long-term potential of non-harvest Pinus radiata plantations for the facilitation and restoration of a natural forest community dominated by indigenous woody species. We investigated the relationship between indigenous regeneration and light levels and the hypothesis that proximity to indigenous seed sources is critical. We studied nine Pinus radiata stands of different ages located within Kinleith Forest, which is a large (ca. 66 000 ha) commercial exotic plantation forest located in New Zealand’s central North Island. \u0000Methods: We constructed a chronosequence of P. radiata plantation stands aged 2–89 years to represent long-term natural forest regeneration following plantation establishment. We surveyed structural, compositional and contextual aspects of this secondary succession and compared these results with an old-growth indigenous forest reference site located within the study area. \u0000Results: The exotic P. radiata canopy facilitated a regeneration trajectory characterised by shade-tolerant indigenous forest species. We found that the structure and composition of P. radiata understories were strongly influenced by stand age and proximity to indigenous forest. Stand age was important from the perspective of creating shaded conditions for the establishment of shade-tolerant woody forest species. Our results suggest that proximal indigenous forest was required for the consistent natural establishment of larger-fruited, bird-dispersed mature forest canopy species in P. radiata plantations. \u0000Conclusions: Our results showed that, even at ecologically isolated sites, the microclimate conditions created by plantation Pinus radiata stands supported a suite of readily-dispersed indigenous forest plants. Based on these results we suggest that non-harvest P. radiata stands provide an important opportunity for the restoration of indigenous forest communities in New Zealand’s production landscapes. Where restoration of forest composition similar to old-growth is the restoration objective, however, interventions might be necessary to direct and accelerate the secondary forest succession. Further replicated study is required into the relationship between native forest proximity and understorey regeneration patterns.","PeriodicalId":19172,"journal":{"name":"New Zealand Journal of Forestry Science","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2019-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43807019","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Exploring forestry options with M?ori landowners: an economic assessment of radiata pine, rimu, and m?nuka","authors":"S. Pizzirani, J. Monge, P. Hall, G. Steward, L. Dowling, P. Caskey, S. McLaren","doi":"10.33494/NZJFS492019X44X","DOIUrl":"https://doi.org/10.33494/NZJFS492019X44X","url":null,"abstract":"Background: A quarter of New Zealand’s land area is currently covered in indigenous forest although only indigenous forests on private land can be harvested. In addition, planted exotic forests (~90% Pinus radiata D.Don) cover a further 7% of the land, and these form the main basis of New Zealand’s forestry industry. However, some landowners are seeking to plant a more diverse range of species (including New Zealand indigenous species) that can be managed in different ways to produce a range of products. \u0000Methods: A “cradle-to-gate” life cycle-based economic assessment of three forestry scenarios was undertaken in collaboration with members of Ng?ti Porou, an indigenous M?ori tribe. The three scenarios were: (1) “business as usual” (i.e. intensive management of radiata pine); (2) continuous-cover forestry management of the indigenous coniferous tree species rimu (Dacrydium cupressinum Lamb.); and (3) intensive production-scale forestry of the indigenous scrub species m?nuka (Leptospermum scoparium J.R.Forst. & G.Forst.). Using a 120-year timeframe, discount rates and opportunity costs were applied and a flat- and steep-land comparative analysis was performed (for radiata pine and rimu). \u0000Results: The Net Present Value (NPV) was calculated for each scenario and showed that, on flat land, only the m?nuka scenario is profitable. However, applications of discount rates can result in a negative NPV, as is the case with the radiata pine and rimu scenarios. On steep land, both the radiata pine and rimu steep-land scenarios have improved NPV returns due to a lower opportunity cost. On steep land, radiata pine is generally profitable with a discount rate of 6% or lower and a stumpage rate of over $100 m3 and rimu is generally profitable with a discount rate of 2% or lower and a stumpage rate of over $650 m-3. \u0000Conclusions: This analysis demonstrates the importance of strategically considering what tree species to plant, what slope of land to plant them on, and what forest management technique to utilise. Furthermore, this analysis highlights the importance of choosing appropriate discount rates and the effect of other inherent assumptions, such as opportunity cost.","PeriodicalId":19172,"journal":{"name":"New Zealand Journal of Forestry Science","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2019-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49068253","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Trends in discount rates used for forest valuation in New Zealand","authors":"B. Manley","doi":"10.33494/NZJFS492019X48X","DOIUrl":"https://doi.org/10.33494/NZJFS492019X48X","url":null,"abstract":"Background: The discount rate is a key input for estimating the market value of a forest. Data collected in surveys of forest valuers from 1997 to 2017 indicate a reduction in implied discount rate (IDR) over time with lower IDRs for larger forests. The purpose of this study was to formally analyse these trends. \u0000Methods: There are three steps to the analysis:1. Relationships were developed for the IDR data from 1997 to 2017;2. Further relationships were developed for IDR data from 2009 to 2017 for which forest size (i.e. net stocked area) rather than just size class is available; and3. Detailed forest transaction data from 2011 to 2017 were used to develop a model to estimate average crop value from key variables including discount rate. This process allowed an analysis to confirm whether or not trends in discount rate with time and forest size were significant. \u0000Results: Analysis of the implied discount rate (IDR) revealed that the reduction over time is significant and that the discount rate for large forests (>10,000 ha) has declined more than for smaller forests. Analysis of data from 2009, for which forest size rather than size class is available, showed that forest area has a significant effect on IDR. Finally, the discount rate within the crop-value model, developed using transaction data collected since 2011, was found to vary with time and forest size; i.e. discount rate decreased as time or forest size increased. \u0000Conclusions: Overall, it can be concluded that the discount rates implicit in New Zealand forest transactions have declined over time, with the scale of the reduction depending on forest size.","PeriodicalId":19172,"journal":{"name":"New Zealand Journal of Forestry Science","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2019-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49436957","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}