Timber Growth Research Articles

Risk Management Behavior of a Forest Owner to Address Growth Risk

We analyze risk management behavior (financial savings versus physical savings) of a private forest owner who values amenities in relation to uncertainty about timber growth. In a two-period model, we study the properties of optimal current and future harvesting and risk management decisions. We show that the forest owner chooses the tool with the highest rate of return unless both risk management instruments are perfect substitutes. We prove that future harvesting is greater under physical savings than under financial savings. Comparative static results on amenity preferences, incomes, forest stocks, timber prices, and opportunity costs are investigated.

Typologisierung des forstwirtschaftlichen Testbetriebsnetzes der Schweiz

Typology of the Swiss Forestry Holding Network The requirements and policies that affect the results of individual forest enterprises are numerous. To develop functioning management and advisory mechanisms, these individual circumstances should be taken into consideration. However, compliance with all the influencing factors is not feasible in practice, wherefore a reduction in the existing complexity is necessary. Multivariate statistical methods allow to use a variety of indicators as a basis for the formation of different types of forest enterprises. The goal to consider the individual operating conditions as completely as possible can be achieved with a multivariate typology. For the Swiss Forestry Holding Network (HDN), the question arises as to whether the results of such a typology can also be reproduced by the currently used biogeographic classification of forest zones. Sixty-six variables with information about structural properties and the business results of 208 Swiss holdings from the years 2008 to 2010 formed the basis of the study data. These variables were reduced to 19 key variables. With the help of principal component and cluster analyses the holdings were divided into four clusters based on these key variables. They differ from each other significantly in most of the key variables. The results of this multivariate typology can be mapped in part by the forest zones of Switzerland. It should be noted that the variable “forest zone” also acts as a multivariate criterion, reflecting the physical and structural requirements of the enterprises. Combined with certain additional information (e.g. timber growth), the results of the multivariate analysis can be even better understood.

A Portfolio Approach for the Forest Asset Dynamic Management under Stochastic Timber Price and Growth

Considering the valuation of forest stands based on revenue from wood sales, concession policy (such as carbon subsidies) and associated costs, the paper focuses on the stochastic control model to study the forest asset dynamic management. The key contribution is to find the optimal dynamic strategy about harvesting quantity in the continual and multiple periods in conditions of stochastic commodity price and timber growth by using portfolio approach. Finally, an analytical optimal strategy is obtained to analyze the quantification relations through which some important conclusions about the optimal forest management can be drawn.

The Enduring Fundamental Framework of Forest Resource Management Planning

Forest resource management planning began in the United States at the turn of the nineteenth century with an emphasis on timber production, sustained yield, and maximum timber growth. A set of well-documented procedures, philosophies, rules, and understandings developed within the forestry profession on the reasons for and requirements of a professionallydeveloped forest resource management plan. For most of the next decade, this framework controlled the development of timber-oriented forest management plans. In the late twentieth century, the forest resource management plans became stewardship- or sustainability-oriented. A broader expansive framework that stressed sustainable forest management developed. However, the framework of both types of plans is fundamentally the same. The natural resource being manipulated is still timber and that is the variable the management plan still focuses on. The set of fundamental underpinnings to the forest management plan has not changed. We describe these underpinnings in terms of both types of forest management plan, as they have remained unchanged over time. Also addressed are the questions of who are the forest owners that plan and what are the differences in the type of forest management plans they prepare.

Family Forest Owners’ Motivation to Control Understory Vegetation: Implications for Consulting Forestry

Forest vegetation management has evolved as a recognized component of intensive forest management practice. It involves the management of competing vegetation necessary to obtain the high yields expected in modern forest plantations via control of interfering plants that influence regeneration outcome, impact timber stand development, and limit native plant and wildlife diversity. It includes cultural control, fire control, mechanical control, biological control, and chemical control. The public perception of forest vegetation management, especially chemical control, is sometimes negative due to health and environmental concerns. It is an important tool in the forest management alternatives available to consulting foresters managing family forest lands (the vast majority of private forest land in the United States). We report on a study that addresses the motivations of family forest owners that implement forest vegetation management practices and the motivation of those who chose not to implement after forester recommendations to do so. For those who do implement forest vegetation management, improvement of wildlife habitat and increased timber growth was the main motivation. For those who did not, cost was the main concern. Size of forest holding plays a major role in determining who will practice intensive forestry.

Carbon loss in drained forestry peatlands in Finland, estimated by re‐sampling peatlands surveyed in the 1980s

The total area of boreal peatlands is about 3.5 million km2 and they are estimated to contain 15–30% of the global soil carbon (C) storage. In Finland, about 60 000 km2, or 60% of the original peatland area, has been drained, mainly for forestry improvement. We have studied C inventory changes on forestry‐drained peatlands by re‐sampling the peat stratum in 2009 at the precise locations of quantitative peat mass analyses conducted as part of peatland transect surveys during the 1980s. The old and new profiles were correlated mainly by their ignition residue stratigraphies; at each site we determined a reference level, identifiable in both profiles, and calculated the cumulative dry mass and C inventories above it. Comparison of a total of 37 locations revealed broad variation, from slight increase to marked decrease; on average the 2009 results indicate a loss of 7.4 (SE ± 2.5) kg m−2 dry peat mass when compared with the 1980s values. Expressed on an annual basis, the results indicate an average net loss of 150 g C m−2 year−1 from the soil of drained forestry peatlands in the central parts of Finland. The C balance appeared not to correlate with site fertility (fertility classes according to original vegetation type), nor with post‐drainage timber growth.

Quantifying the net economic benefits of mechanical wildfire hazard treatments on timberlands of the western United States

Mechanical treatment of vegetation is done on public and private lands for many possible reasons, including enhancing wildlife habitat, increasing timber growth of residual stands, and improving resistance to damaging pests. Few studies, however, have focused on the circumstances under which mechanical wildfire hazard reduction treatments can yield positive net economic wildfire benefits for landowners and managers. This study describes an economic assessment tool built from a representative area sample frame inventory of hazardous and potentially treatable timberland in twelve western states of the U.S. Base case parameter assumptions about values at risk, timber product prices, stand re-growth following treatment and wildfire impacts enable an initial estimate of the amount of timberland with positive discounted expected net economic benefits under four policy scenarios. These assumptions are then varied in a Monte Carlo simulation to provide some bounds of uncertainty around base case levels. A policy that allowed optimal prescriptions and product sales and which incorporates wildfire costs and benefits would result in more than 25% of treated area with positive net benefits. This is reduced somewhat if wildfire reduction costs and benefits are not considered, and reduced again to 14% when large trees are excluded from product sales. A policy that prohibits sale of products from these treatments results in less than 1% of area with positive net benefits.

A national and international analysis of changing forest density.

Like cities, forests grow by spreading out or by growing denser. Both inventories taken steadily by a single nation and other inventories gathered recently from many nations by the United Nations confirm the asynchronous effects of changing area and of density or volume per hectare. United States forests spread little after 1953, while growing density per hectare increased national volume and thus sequestered carbon. The 2010 United Nations appraisal of global forests during the briefer span of two decades after 1990 reveals a similar pattern: A slowing decline of area with growing volume means growing density in 68 nations encompassing 72% of reported global forest land and 68% of reported global carbon mass. To summarize, the nations were placed in 5 regions named for continents. During 1990–2010 national density grew unevenly, but nevertheless grew in all regions. Growing density was responsible for substantially increasing sequestered carbon in the European and North American regions, despite smaller changes in area. Density nudged upward in the African and South American regions as area loss outstripped the loss of carbon. For the Asian region, density grew in the first decade and fell slightly in the second as forest area expanded. The different courses of area and density disqualify area as a proxy for volume and carbon. Applying forestry methods traditionally used to measure timber volumes still offers a necessary route to measuring carbon stocks. With little expansion of forest area, managing for timber growth and density offered a way to increase carbon stocks.

Forgotten Outcomes for Rural Areas in Central Policy-Making: The Case of Blue Gums in Australia

The expansion of private forestry and the partnership between government and private sector timber growers and processors highlights the issues associated with a functionally based rather than a place based approaches to changing patterns of land use in rural areas. Rural development through blue gum forestry was promoted as a means of revitalising rural communities, providing both economic and social gains to regional areas. The purpose of this study is to examine the economic consequences of policies designed to promote plantation forestry at a local level. It concludes that while plantation forestry may bring benefits to the national economy, these benefits may not be apparent at a local level especially if the industry operates in competition with a viable alternative.

Optimization of irregular-grid cellular automata and application in risk management of wind damage in forest planning

This study demonstrated how cellular automata, using irregular grids, can be used to minimize the risk of wind damage in forest management planning. The development of a forest in central Finland was simulated for a 30-year period with three subplanning periods. A forest growth and yield model in association with a mechanistic wind damage model was applied to simulate forest growth and to calculate the length of stand edges at risk. Irregular cellular automata were utilized to optimize the harvest schedules for reducing the risk and maintaining a sustainable harvest level. The cellular automata produced rational results, i.e., new clearcuts were often placed next to open gaps, thereby, reducing the amount of vulnerable stand edges. The algorithms of the cellular automata rapidly converged and optimized the harvest schedules in an efficient way, especially when risk minimization was the only objective. In a planning problem that included even-flow timber harvesting objectives (harvest level equal to the total timber growth), the targets were almost achieved. Although the cellular automaton had slightly larger deviations of harvesting from the targets compared with other tested heuristic approaches (simulated annealing, tabu search, and genetic algorithms), it had the best performance when minimizing the expected wind damage.

The European carbon balance. Part 4: integration of carbon and other trace‐gas fluxes

AbstractOverviewing the European carbon (C), greenhouse gas (GHG), and non‐GHG fluxes, gross primary productivity (GPP) is about 9.3 Pg yr−1, and fossil fuel imports are 1.6 Pg yr−1. GPP is about 1.25% of solar radiation, containing about 360 × 1018 J energy – five times the energy content of annual fossil fuel use. Net primary production (NPP) is 50%, terrestrial net biome productivity, NBP, 3%, and the net GHG balance, NGB, 0.3% of GPP. Human harvest uses 20% of NPP or 10% of GPP, or alternatively 1‰ of solar radiation after accounting for the inherent cost of agriculture and forestry, for production of pesticides and fertilizer, the return of organic fertilizer, and for the C equivalent cost of GHG emissions. C equivalents are defined on a global warming potential with a 100‐year time horizon. The equivalent of about 2.4% of the mineral fertilizer input is emitted as N2O. Agricultural emissions to the atmosphere are about 40% of total methane, 60% of total NO‐N, 70% of total N2O‐N, and 95% of total NH3‐N emissions of Europe. European soils are a net C sink (114 Tg yr−1), but considering the emissions of GHGs, soils are a source of about 26 Tg CO2 C‐equivalent yr−1. Forest, grassland and sediment C sinks are offset by GHG emissions from croplands, peatlands and inland waters. Non‐GHGs (NH3, NOx) interact significantly with the GHG and the C cycle through ammonium nitrate aerosols and dry deposition. Wet deposition of nitrogen (N) supports about 50% of forest timber growth. Land use change is regionally important. The absolute flux values total about 50 Tg C yr−1. Nevertheless, for the European trace‐gas balance, land‐use intensity is more important than land‐use change. This study shows that emissions of GHGs and non‐GHGs significantly distort the C cycle and eliminate apparent C sinks.

Do ecological networks in South African commercial forests benefit grassland birds? A case study of a pine plantation in KwaZulu-Natal

Grasslands in South Africa have been extensively transformed and fragmented, but are poorly protected. Commercial afforestation poses a particular threat to grassland biodiversity because areas suitable for forestry coincide with those supporting the greatest richness of endemic and threatened biota. To comply with international forestry standards, commercial timber growers leave “ecological networks” of interconnected open corridors within plantations: however, the value of these networks for conservation is unclear. This study investigated how bird community composition, richness and density were influenced by habitat extent, connectivity and quality in a grassland ecological network in a forestry plantation in KwaZulu-Natal, South Africa. We surveyed birds and measured local vegetation characteristics throughout the network. There were at least five open habitat types within the network and bird communities responded clearly to differences between these habitats: all network communities showed a distinct shift away from those typical of control grasslands. There were three distinct groups of species in the network: (1) grassland specialists, (2) habitat generalists and (3) non-grassland species. Grassland specialists were restricted to areas that are burned regularly and to large, contiguous open areas or wide grassland corridors. We found no evidence for the importance of physical connectivity among open habitats for birds in the study area. Instead, it appears that the establishment of so-called ecological networks at this scale has created much unsuitable habitat for grassland specialist species. We suggest consolidation of open areas and a rotational, biennial burning regime as a more appropriate management strategy for commercial plantations in these Critically Endangered montane grasslands.

An Analytical Optimal Strategy of the Forest Asset Dynamic Management under Stochastic Timber Price and Growth: A Portfolio Approach

Considering the valuation of forest stands based on revenue from wood sales, concession policy (such as carbon sub- sidies) and associated costs, the paper focuses on the stochastic control model to study the forest asset dynamic manage- ment. The key contribution is to find the optimal dynamic strategy about harvesting quantity in the continual and multiple periods in conditions of stochastic commodity price and timber growth by using portfolio approach. Finally, an analytical optimal strategy is obtained to analyze the quantification relations through which some important conclusions about the optimal forest management can be drawn.

Androgen-promoted traits and intellectual abilities and interests

Androgens affect many physical traits, especially ones having to do with muscularity, voice timber, and hair growth. The present study was undertaken to assess the influence of androgens on human intellectual abilities and interests. A large sample of North American college students self-assessed their intelligence, academic interests, grade point averages, and achievement test scores. These traits were compared to scores on eight androgen-influenced traits. Numerous modest but statistically significant relationships were found between androgen-promoted physical traits and self-reported intelligence, especially among males. However, virtually no significant correlations were found between these androgen-promoted traits and grades, class rank, or ACT/SAT scores. Regarding academic interests, significant positive associations with androgen-promoted traits were found, with the strongest links involving the natural sciences and mathematics. This study suggests that androgens influence intelligence, but that they primarily do so by impacting intellectual interests in the physical environment and mathematical reasoning.

Liability, Regulation, and Endogenous Risk: The Incidence and Severity of Escaped Prescribed Fires in the United States

Abstract Prescribed fire is a useful but risky method for reducing the general wildfire risk and improving wildlife habitats, biodiversity, timber growth, and agricultural forage. In the past 15 years, laws to further promote the use of prescribed fire have been adopted in several states. This article examines the effect of liability laws and common regulations on the incidence and severity of escaped prescribed fires in the United States from 1970 to 2002. Regression results show that stringent statutory liability laws and regulations tend to reduce the number and severity of escaped prescribed fires on private land but not on federal land, where state liability laws do not directly apply. An economic motivation—based on the explicit recognition in these statutes of the perceived public benefits provided by prescribed fires—for the recent changes in statutory laws is provided.

Regional habitat selection of large gliding possums at forest stand and landscape scales in southern Queensland, Australia: II. Yellow-bellied glider ( Petaurus australis)

Habitat selection of the yellow-bellied glider ( Petaurus australis) was investigated throughout the forests and woodlands of the southern Queensland region. Forest stand- and landscape-scale habitat variables were recorded or derived for 506 sites that were systematically located in the region using a random stratified survey design. Using an information-theoretic model selection approach, logistic regression models predicting the occupancy of gliders at the stand- and landscape-scales were developed and compared. The model receiving strongest support included both stand- and landscape-scale explanatory variables. At the stand scale, yellow-bellied gliders were selective with regard to the floristic characteristics of the overstorey, with increased probability of occupancy in dry, mixed eucalypt open forest as compared with non-eucalypt dominant forests or eucalypt woodland structural formations. The probability of glider occupancy increased with basal area of grey gum species Eucalyptus longirostrata or E. biturbinata, species known to be important for sap feeding by gliders in southern Queensland. The occurrence of the yellow-bellied glider was predicted to decrease with increased logging intensity, and also in habitat patches with increased edge relative to area, a landscape-scale variable. The species was also predicted to decrease with another landscape-scale variable, increased habitat clearing within a 1-km radius, although this variable was revealed as an unreliable predictor using odds ratio. The implementation of an intensive, once-only, timber-harvesting regime involving the removal of trees >40 cm diameter in 8% of potential yellow-bellied glider habitat in the region is likely to greatly reduce habitat suitability, unless a landscape-scale management approach is instigated. The introduction of the regime in a further 15% of potential glider habitat is currently being debated. Off-reserve management of yellow-bellied glider habitat will be essential, and the development, introduction and implementation of sustainable timber harvesting guidelines for private timber growers needs to be supported.

Silviculture that sustains: the nexus between silviculture, frequent prescribed fire, and conservation of biodiversity in longleaf pine forests of the southeastern United States

The longleaf pine (Pinus palustris Mill.) forest ecosystems of the US southeastern Coastal Plain, among the most biologically diverse ecosystems in North America, originally covered over 24 × 106 ha but now occupy less than 5% of their original extent. The key factor for sustaining their high levels of diversity is the frequent application of prescribed fire uninterrupted in time and space. Pine fuels, critical to application of fire and regulated by canopy distribution, provide the nexus between silviculture and fire management in this system. Typical silvicultural approaches for this type were, in large part, developed to maximize the establishment and growth of regeneration as well as growth and yield of timber, with much less regard to how those practices might influence the ability to sustain prescribed burning regimes or the associated biodiversity. However, many landholdings in the region now include conservation of biodiversity as a primary objective with sustained timber yield as an important but secondary goal. This review synthesizes the literature related to controls of biodiversity for longleaf pine ecosystems, and silvicultural approaches are compared in their ability to sustain natural disturbance such as fire and how closely they mimic the variation, patterns, and processes of natural disturbance regimes while allowing for regeneration.

Hydrogeological influences on forest community type along forest–peatland complexes in coastal British Columbia

The prospect of harvesting forest–peatland systems in the coastal western hemlock forest region of British Columbia has created the need for an understanding of the interrelationship between topography, groundwater flow, and site productivity. Detailed topographic mapping including the use of ground-penetrating radar coupled with point measurements of specific yield, bulk density, saturated hydraulic conductivity, and groundwater level were used to determine the characteristics of groundwater flow along forest–peatland complexes. A topographic index was then used to characterize the spatial distribution of groundwater flow and site conditions (as represented by water table depth and organic horizon thickness) influencing forest community type. Forest community type mean index decreased from open peatland to upland forest. Areas with high slope indices had thicker organic horizons (0.7–1.8 m), water tables closer to the surface (0–0.2 m), and higher soil moisture contents (46–92%). These conditions affect successional dynamics and favour the invasion of hydrophytic species such as Sphagnum mosses. Areas with low slope index values were associated with shallower organic horizons (<0.4 m), deeper water table (0.3 to >1.6 m), and drier soil moisture (35–76%), favouring more prolific timber growth.

Effects of resin tapping on optimal rotation age of pine plantation

This paper analyses the effects of resin benefit on the optimal rotation age of Simao pine plantation. Timber growth and resin yield functions were first derived, and then an integrated formulation for Hartman rotation was solved by taking both timber and resin benefits into consideration through numerical optimization. Empirical results indicate that: (1) the inclusion of resin benefit results in lengthening optimal rotation age; (2) resin benefit has a greater effect on rotation age when discount rate is low than when it is high, ceteris paribus; (3) with an improvement of site productivity, resin benefit has a decreasing effect on rotation age, other factors being constant. These effects are also true with respect to benefit gains in present value.

Economic Returns Model for Silvicultural Investments in Young Hardwood Stands

Abstract Despite covering the majority of forestland in the southern United States, hardwoods continue to be grown primarily in natural, extensively managed stands. One reason has been that hardwood growth increases resulting from active management have been small in comparison with unmanaged stands. Recent studies indicate, however, that the productivity responses of very young (ages 1–15 years) natural even-aged hardwood stands to silvicultural treatments such as fertilization, herbicide release, or stocking control can yield large productivity increases, demonstrating the potential for faster timber growth of higher quality in shorter rotations. In determining the extent to which these productivity increases may justify investment in various silvicultural treatments, we have developed hardwood management scenarios representing productivity increases of up to 33%. Timber revenues have been estimated and rates of return compared across various management intensities. Results indicate that the assumed productivity increases would readily pay for treatments such as fertilization, herbaceous release, and stocking control while yielding rates of returns equal to or greater than those generated by untreated stands. South. J. Appl. For. 28(4):179–184.