Socioeconomic Conditions Affecting Smallholder Timber Management in Gunungkidul District,Yogyakarta Special Region,Indonesia

Indonesia is one of the largest teak timber producers in the world. The Javanese State Forest Company has been a major producer of teak timber in Indonesia; however, log production decreased drastically due to severe illegal logging after the collapse of Suharto regime. In contrast, small-scale private forests (PFs) owned by local farmers have expanded and are expected to be a new source of teak timber. Long rotation is a critical factor in producing a larger diameter log with a higher heartwood proportion. However, harvest timing in PFs is traditionally decided based on individual farmers’ needs even if trees are still young and of small diameter. Therefore, traditional harvesting is an obstacle to producing high-quality teak timber. The objectives of this study are to (1) identify the household economies and PF management styles of local farmers, (2) characterize the local farmers who conduct traditional harvesting, and (3) suggest key considerations for PF policymaking. Key informant interviews and semi-structured interviews with local farmers were conducted in three villages in Gunungkidul district, Yogyakarta Special Region. The study identified the household economies, the ownership and management structures, and the traditional harvesting in PFs in the three villages, and reaffirmed diversity and complexity of PFs. It appears that PF management is influenced by topographic and socioeconomic conditions and differs widely across villages. Therefore, it is important to consider the diversity and complexity of PFs in PF policymaking.     

Exploring adaptation to climate change in the forests of central Nova Scotia, Canada

The threat of climate change is now recognized as an imminent issue at the forefront of the forest sector. Incorporating adaptation to climate change into forest management will be vital in the continual and sustainable provision of forest ecosystem services. The objective of this study is to investigate climate change adaptation in forest management using the landscape disturbance model LANDIS-II. The study area was comprised of 14,000 ha of forested watersheds in central Nova Scotia, Canada, managed by Halifax Water, the municipal water utility. Simulated climate change adaptation was directed towards three components of timber harvesting: the canopy-opening size of harvests, the age of harvested trees within a stand, and the species composition of harvested trees within a stand. These three adaptation treatments were simulated singly and in combination with each other in the modeling experiment. The timber supply was found to benefit from climate change in the absence of any adaptation treatment, though there was a loss of target tree species and old growth forest. In the age treatment, all trees in a harvested stand at or below the age of sexual maturity were exempt from harvesting. This was done to promote more-rapid succession to climax forest communities typical of the study area. It was the most effective in maintaining the timber supply, but least effective in promoting resistance to climate change at the prescribed harvest intensity. In the composition treatment, individual tree species were selected for harvest based on their response to climate change in previous research and on management values at Halifax Water to progressively facilitate forest transition under the altered climate. This proved the most effective treatment for maximizing forest age and old-growth area and for promoting stands composed of climatically suited target species. The size treatment was aimed towards building stand complexity and resilience to climate change, and was the most influential treatment on the response of timber supply, forest age, and forest composition to timber harvest when it was combined with other treatments. The combination of all three adaptation treatments yielded an adequate representation of target species and old forest without overly diminishing the timber supply, and was therefore the most effective in minimizing the trade-offs between management values and objectives. These findings support a diverse and multi-faceted approach to climate change adaptation.     

The economics of timber supply: Does it pay to reduce harvest levels?

Sustained yield policies designed to ensure an even annual flow of timber harvests remain the most common approach to forest management on public lands in Canada. Such policies have been criticized on the environmental grounds that timber production is emphasized at the expense of other values, and on the economic grounds that policy-makers try to maximize the harvests level without regard for economic optimality (measured by whether or not revenues cover variable costs of production). In a case study from Northern Ontario, we used a spatially explicit harvest scheduling model to evaluate financial outputs for various scenarios, introducing different timber flow constraints, as well as varying utilization policies. We show that current policies do contribute to firms harvesting at uneconomic levels. More specifically, our results show that reducing harvest levels could increase firm profitability (measured in an increase in net revenues associated with harvesting operations). We estimate that to meet the annual allowable cut (AAC) of approximately 375,000 cubic metres (m³), the firm loses $500,000 annually (measured by the amount by which total harvesting costs exceed log values delivered at the mill). Reducing the target AAC to just under 300,000 m³ leads to a reversed situation, harvesting revenues now exceeding costs by $1.2 million annually. Dropping the even flow constraint leads to even higher annual profitability of $3.5 million, with the drawback that harvesting levels show significant variation over the 100-year planning period. Our results also show that the largest factor influencing the level of profitability is attributed to access costs (principally roading costs). In this case, other harvesting policies, such as utilization standards, may not be significant factors affecting costs in this region of Northern Ontario.     

A simulation model for economic analysis of timber/forage production alternatives in rocky mountain aspen stands

A simulation model was developed to analyze possibilities for timber and forage joint production in Rocky Mountain aspen stands. Given harvest possibilities from timber yield tables and information concerning site characteristics, the model calculates the physical production levels for timber and forage, and then uses these figures to make an economic analysis based on present net worth and financial maturity criteria. The model was applied to different sets of sites, harvest possibilities, and costs and revenues. The results indicated that the optimal joint production strategy varies with the economic criterion, the discount rate and harvest strategy.     

Determining the optimal selective harvest strategy for mixed-species stands with a transition matrix growth model

An optimization model was developed to determine the optimal harvesting strategy needed for uneven-aged mixed-species stands in the Changbai Mountain region of northeast of China. The model takes into account four variables including residual basal area (RBA), the diameter of the largest tree, harvest cycle and a constant representing the ratio of the number of trees in a given diameter class to those in the next larger diameter class (‘q’). According to model simulations, under the objective of maximizing net revenue, the optimal harvesting strategy is defined when the residual basal area equals to 19 m² ha⁻¹, the diameter of the largest tree equals to 44 cm, q 1.3 and the harvest cycle equals to 20 years. If the objective is to maximize the total volume yield, the optimal harvesting strategy is defined when RBA equals to 13 m² ha⁻¹, the diameter of the largest tree equals to 36 cm and the constant ‘q’ equals to 1.9 and the harvest cycle equals to 15 years.     

Family forest owner preferences for biomass harvesting in Massachusetts

U.S. forests, including family-owned forests, are a potential source of biomass for renewable energy. Family forest owners constitute a significant portion of the overall forestland in the U.S., yet little is known about family forest owners' preferences for supplying wood-based biomass. The goal of this study is to understand how Massachusetts family forest owners feel about harvesting residual woody biomass from their property. The study estimates the probability that Massachusetts landowners will harvest biomass as part of a timber harvest using data from a survey of 932 Massachusetts family forest owners. Logistic regression results suggest that the likelihood of harvesting for biomass is quite low, and that the supply of participation in biomass harvesting is inelastic with respect to price. These low probabilities may be due to the method used to account for preference uncertainty, as well as the unique nature of Massachusetts forests, forest markets, and landowner attitudes in comparison to other states (e.g., Minnesota). The study suggests that it would be more effective to target renewable energy policy toward different regions and/or markets rather than develop a uniform national policy.     

Optimal harvesting time in single‐ and multiple‐purpose forest management

In single‐purpose timber producing forestry, the optimal harvesting time occurs when the net revenue on the stumpage value equals the cost of renting the land (the land‐use cost) minus the change in land value.

In multiple‐purpose forestry, the optimal time for harvesting occurs when the sum of the net revenues of the stumpage value and the amenity value is equal to the cost of renting the land minus the change in the land value. This land value is the sum of the land value for timber production and the land value for amenity services in the case of combined management of timber and amenity‐resources.     

Lessons from the Queensland Rainforests

Commercial timber harvesting commenced in the tropical rainforests of north Queensland in 1873 and ceased in 1988 following their inclusion on the World Heritage List. The evolution of forest policy, management and research is reviewed, and strengths and weaknesses are highlighted. Between 1950-85, eight estimates of the sustainable yield varied ten-fold. Discrepancies were due to different assumptions regarding management, and to errors in estimating net productive areas and growth rates. During 1950-85, the allowable cut (130,000-207,000 m3/ann) exceeded sustained yield estimates (60,000-180,000 m3/ann), but the actual harvest (90,000-205,000 m3/ann) remained less than the allowable cut. The allowable cut was reduced to a sustainable level in 1986, and commercial logging ceased in 1988. It is not certain that the harvest during the 1980s was sustainable, but several indicators suggest that it probably was sustainable. Lessons for other tropical timber producers are highlighted.     

Approach to the estimation of red heart occurrence in Fagus sylvatica based on geometric relationships between branch scar development and knot dimensions

Abstract

The effect of branch scars on the initiation and occurrence of red heart in beech (Fagus sylvatica L.) was studied on 17 trees with red heartwood and 14 trees with no discoloured heartwood, all of which were selected from a 120-year-old high-forest stand in Germany. Logistic regression was used to predict the probability of red heart occurrence for a given tree. The model was based on individual probabilities derived from geometric relationships between scar and knot morphologies, and integrated the diameter at breast height. Using this model, 27 of 31 trees were correctly classified, and the two groups of trees were clearly distinguished by probabilities below 0.25 and above 0.85 (with one exception). Given the constitution of the model, only 17 of 616 scars were found to initiate red heart formation, and the parameters of mechanistic variables were strongly correlated. The results suggest specifying the relationship between scars, knots and red heart, and extending the scope of the model.     

An Economic Evaluation of a Small-Scale Timber Harvesting Operation in Western Maryland, USA

As forests of the eastern United States become fragmented into smaller ownership parcels, there is a growing need for timber harvesting contactors who can economically harvest timber and perform silvicultural operations on small tracts. Traditional large-scale harvesting operators are ill-suited for work on small parcels, due to their high fixed costs. By contrast, small-scale operators, characterized by few workers and low capital investment, offer an opportunity to serve this landowner segment. This paper presents financial and productivity results from a small-scale timber harvesting pilot study conducted on small forested parcels in western Maryland, USA. Acceptable financial performance is possible for these operations, provided that the operator pays close attention to the important factors determining productivity and profitability, including: (1) average tree volume, (2) net delivered price, (3) time utilization, and (4) distance to the site. Although profitable harvesting of saw log quality trees on parcels less than 10 ha is possible, harvesting of small or poor-quality trees remains economically unattractive.     

基于最优轮伐期模型的超限额采伐现象及其约束机制分析

文中将最优轮伐期模型应用于对超限额采伐现象的研究,认为由于国有森工企业的利润大多来自于木材销售收入,而企业领导的任期是有限的,他们只关心自己任期内的业绩,导致企业经营的目标实际上是短期木材收益的最大化,而不是我们所期待的可持续木材与生态综合收益最大化,甚至也不是私人拥有森林时所追求的长期木材收益的最大化。他们会设法突破政府设定的采伐限额,增加采伐量,造成森林资源加速衰退的不良后果,不仅生态功能迅速萎缩,木材产量也无法长期维持下去。同样的情形在国有林场短期租赁给私人经营时也极易发生。为尽量杜绝这种现象,有必要通过建立有效的监督和惩罚机制使超采所带来的额外收益小于被发现时上缴罚款的数学期望值,以此从根本上遏制住企业超限额采伐的动机。     

Effects of experimental forest harvesting on oribatid mite biodiversity

Ecosystem-based management (e.g. partial cut harvesting) attempts to mimic natural forest dynamics and maintain structural complexity, and this less intense harvesting may minimize the impact on forest floor fauna and help maintain soil system biodiversity. We tested how different experimental harvesting regimes affect the diversity, abundance and composition of Oribatida at the sylviculture et aménagement forestiers écosystémique (SAFE) research forest located in the Abitibi region in NW Québec. Litter and soil were sampled in June 2006 in the mixedwood boreal forest at SAFE where the following treatments were applied and replicated three times: clear cut harvest, 1/3 partial cut harvest, 2/3 partial cut harvest, prescribed burn (after clear cut harvest) and uncut control. Eight years after harvest, partial cuts had more similar species composition to the uncut control within their respective blocks; however, burned habitat showed a shift in species dominance patterns and harboured a relatively distinct composition and species richness compared to treatments. With the exception of samples from clear cuts, species composition of the harvesting treatments was more similar within blocks than among blocks, suggesting that for less intense harvesting practices, spatial scale (i.e. regional factors) could have a greater influence in structuring oribatid assemblages than harvesting regime, but in more severe disturbances such as burn-after-clear cut harvest, habitat is altered enough to affect oribatid biodiversity.     

Optimal forest rotation periods: integrating timber production and carbon sequestration benefits in Pinus tabulaeformis plantations on the Loess Plateau,P.R. China

Determining the optimal rotation period was a crucial component of forest sustainable management strategies, especially under climate change. This paper had two objectives: (1) to determine the economic benefits and optimal rotation periods for timber production when coupled to carbon sequestration, as predicted by time series prediction models for Pinus tabulaeformis plantations in China; and (2) to evaluate how different carbon prices and interest rates affected optimal rotation periods using the forest land expectation value. The results suggested that time series prediction models were valuable for estimating timber volumes and carbon sequestrations based on surveys of different-aged stands. Importantly, since integrating carbon sequestrations into timber production benefits did not increase optimal rotation periods, this should promote P. tabulaeformis plantation management. In the sensitivity analysis, a higher carbon price increased the profitability of carbon sequestration and timber production, but not optimal rotation periods, though they were reduced under higher interest rates. In conclusion, incorporating both timber production and carbon sequestration benefits would sharply increase forest-based revenues, while realizing the carbon sequestration potential of P. tabulaeformis plantations. This approach was clearly useful to the development of reforestation/afforestation projects trying to mitigate climate change and also provided a theoretical basis for sustainable forest management.     

An integrated assessment approach to optimal forest bioenergy production for young Scots pine stands

Background: Bioenergy is re-shaping opportunities and imperatives of forest management. This study demonstrates,through a case study in Scots pine(Pinus sylvestris L.), how forest bioenergy policies affect stand management strategies.Methods: Optimization studies were examined for 15 Scots pine stands of different initial stand densities, site types, and temperature sum regions in Finland. Stand development was model ed using the Pipe Qual stand simulator coupled with the simulation-optimization tool Opti For Bioenergy to assess three forest bioenergy policies on energy wood harvest from early thinnings.Results: The optimal solutions maximizing bare land value indicate that conventional forest management regimes remain optimal for sparse stands. Energy harvests occurred only when profitable, led to lower financial returns. A forest bioenergy policy which included compulsory energy wood harvesting was optimal for denser stands. At a higher interest rate(4 %), increasing energy wood price postponed energy wood harvesting. In addition, our results show that early thinning somewhat reduced wood quality for stands in fertile sites. For less fertile sites, the changes were insignificant.Conclusions: A constraint of profitable energy wood harvest is not rational. It is optimal to carry out the first thinning with a flexible forest bioenergy policy depending on stand density.     

目标规划与轮伐公式确定森林收获的比较分析

利用中国林科院热带林业实验研究中心2009年森林资源二类调查数据,分别利用目标线性规划与传统森林轮伐公式计算热林中心马尾松纯林和杉木纯林用材林年采伐量,比较分析同一个经理期（2009—2019年）两种计算方法的不同;结果表明：轮伐公式计算的采伐量一般偏大,且目标规划单位面积年经济收益是轮伐公式获得经济效益的10 20倍。利用目标规划法在同时实现材积收获量最大、出材量最大、净现值收益最大的目标前提下,对森林结构进行调整,使资源分布满足可持续经营的要求,即尽可能达到法正状态。     

红豆树立木的主要性状特征研究(Ⅱ)

红豆树胸高心材出现在10 a以后,相同立地环境且同龄的红豆树立木,其心材出现有迟早和大小的差别.心材材积与胸径呈幂函数关系、心材直径与胸径呈直线关系、心材直径与树高呈对数关系、心材直径与冠长呈直线关系、心材直径比率与胸径呈自然对数函数关系;红豆树心材率达2倍以上标准差进行优树选择时,可望选出选择差较大、心材比率在90.2%的优树.Ⅰ级侧枝枝粗与胸径、冠长呈直线关系,与树高关系、枝下高不存在有实际意义的相关关系.红豆树林分中,通直的Ⅰ级木占调查样本数的33.7%、Ⅱ级木占21.1%、Ⅲ级木占24.7%、Ⅳ级木占17.5%、Ⅴ级木占3%.冠长与胸径呈直线关系、与树高呈对数关系,冠幅与胸径呈对数关系.     

Economic analysis of harvesting behavior using the modified Gentan probability theory

In the past studies on the Gentan probability theory, economic factors, such as the price of logs and the interest rate, have not been embedded into the derived stochastic model due to the limitation of the underlying assumptions. This has lead to misleading results of economic analysis for harvesting behavior based on the Gentan probability theory. In this paper, economic analysis of harvesting behavior was conducted by extending the Gentan probability theory. Since the proposed stochastic process can incorporate a nonstationary growth function, economic analysis of harvesting behavior was easily implemented. Experimental analysis of economic factors showed that change in the price of logs, the interest rate and harvest related costs affected the Gentan probability distribution. Although the analysis is still hypothetical, the results imply the potential use of the Gentan probability theory to predict the forest owners' harvesting behavior.     

Initial responses of woody vegetation, water quality, and soils to harvesting intensity in a Texas bottomland hardwood ecosystem

Sustainable management of bottomland hardwood forest ecosystems requires a knowledge of responses to management impacts, including timber harvesting. The effects of clearcutting and partial cutting on woody vegetation regeneration dynamics, surface and groundwater quality, soil physical properties, and soil respiration were tested in a bottomland hardwood ecosystem in southeastern Texas, USA, through comparison with non-cut control areas. Overstory removal only slightly affected composition of woody vegetation regeneration 1 year after harvesting compared with pre-harvest composition. Initial composition in both cutting treatments appeared to be the strongest determinant of post-harvest composition, at least for the first year after harvesting. There were few significant differences in groundwater properties when harvesting treatments were compared with control areas during a 17-month period following harvest. Turbidity, temperature, electrical conductivity, dissolved O₂, NH₄-N, NO₃-N, and PO₄-P of streamwater did not vary significantly among treatments. Slight decreases in total and macroporosity were observed in association with higher bulk densities at 0–5 cm depth in the clearcut and partial cut treatments. Saturated hydraulic conductivity values did not decline significantly with treatment intensity. No significant differences among treatments in measured soil physical properties were observed at 5–10 cm depth. Although in situ soil respiration increased with harvest intensity, treatment had no significant effect on mineral soil respiration. In summary, most variables showed only slight response to harvesting, thereby indicating that harvesting practices can be conducted with minimal initial impacts on measured response variables.     

Scenario analyses on the effects of fertilization,improved regeneration material,and ditch network maintenance on timber production of Finnish forests

We used national scenario analyses to examine the effects of fertilization, use of improved regeneration material and ditch network maintenance (DNM), both separately and simultaneously, on timber production of Finnish forests under the current climate. We also analyzed how the area of artificial regeneration, forest fertilization, and DNM developed in different management and harvesting intensity scenarios. The initial data were obtained from the 11th National Forest Inventory of Finland, excluding protected forests. Four sets of even-flow harvesting scenarios with annual timber harvest targets of 60, 70, 80, and 90 million m³ were developed for 90-year simulation period. Use of improved material in artificial forest regeneration was assumed to result in 10% higher diameter and height increment compared to naturally regenerated seedlings. Sub-xeric pine-dominated and mesic spruce-dominated sites were fertilized, and 40% of drained peatlands were maintenance-ditched when they fulfilled a set of predetermined criteria for temperature sum, stand basal area, and mean tree diameter. As a result, when fertilization, improved regeneration material, and DNM were all used, the mean annual volume increment over the 90-year simulation period increased by 3.4–5.4 million m³ depending on harvesting intensity. The maximum sustainable harvest of timber would be almost 80 million m³ yr^?1. The simulated fertilization area was about four times larger than the presently fertilized area, and the simulated DNM area was about the same as the current. Fertilization gave the largest additional 90-year volume increment and the DNM the smallest when they were used separately. The use of improved regeneration material gave the largest additional volume increment in southern Finland and fertilization in central and northern Finland.     

Post-breeding bird responses to canopy tree retention, stand size, and edge in regenerating Appalachian hardwood stands

Avian use of even-aged timber harvests is likely affected by stand attributes such as size, amount of edge, and retained basal area, all characteristics that can easily be manipulated in timber harvesting plans. However, few studies have examined their effects during the post-breeding period. We studied the impacts of clearcut, low-leave two-age, and high-leave two-age harvesting on post-breeding birds using transect sampling and mist-netting in north-central West Virginia. In our approach, we studied the effects of these harvest types as well as stand size and edge on species characteristic of both early-successional and mature forest habitats. In 2005-2006, 13 stands ranging from 4 to 10 years post-harvest and 4-21 ha in size were sampled from late June through mid-August. Capture rates and relative abundance were similar among treatments for generalist birds. Early-successional birds had the lowest capture rates and fewer species (∼30% lower), and late-successional birds reached their highest abundance and species totals (double the other treatments) in high-leave two-age stands. Area sensitivity was evident for all breeding habitat groups. Both generalist and late-successional bird captures were negatively related to stand size, but these groups showed no clear edge effects. Mean relative abundance decreased to nearly zero for the latter group in the largest stands. In contrast, early-successional species tended to use stand interiors more often and responded positively to stand size. Capture rates for this group tripled as stand size increased from 4 to 21 ha. Few birds in the forest periphery responded to harvest edge types despite within-stand edge effects evident for several species. To create suitable habitat for early-successional birds, large, non-linear openings with a low retained basal area are ideal, while smaller harvests and increased residual tree retention would provide habitat for more late-successional birds post-breeding. Although our study has identified habitat use patterns for different species in timber harvests, understanding habitat-specific bird survival is needed to help determine the quality of silvicultural harvests for post-breeding birds.