Silva Fennica vol. 40 no. 1 | 2006

Finland has launched a new policy programme (METSO) to enhance conservation of forest biodiversity. In non-industrial private forests, the policy is based on economic incentives and voluntarism on the part of forest owners. While biodiversity conservation is the main target of the policy, social acceptability is considered to be of great importance. This study examined the factors that affect the acceptability of biodiversity conservation contracts among private forest owners, and the amount of compensation needed to keep the forest owners at least as well off as before the contract. Choice experiment method was used to analyse the data that were collected by surveying 3000 Finnish private forest owners. Analysing separately those respondents who were willing to enter into a conservation contract allowed an assessment of the impact of forest owners’ heterogeneity on compensation amount. The results show how the welfare of forest owners shifts when the contract terms are changed. In a base scenario the forest owner was assumed to be the initiator of the contract that would require only small patches of forest to be protected, and would also bind new forest owners over its duration of ten years. For all respondents, the average demand for compensation would be around 224 euros annually. When those always choosing the “no additional conservation” alternative were excluded, the average welfare impact of the base scenario was positive.

• Horne, Finnish Forest Research Institute, Unioninkatu 40 A, FI-00170 Helsinki, Finland E-mail: paula.horne@metla.fi

Compression wood is undoubtedly one of the most important raw material variables in wood based panel manufacturing. This study evaluated effect of compression wood on surface roughness and surface absorption (flow distance) of medium density fiberboards (MDF) manufactured from furnishes of pine (Pinus nigra Arnold var. pallasiana) containing compression wood. Panels were manufactured from two different portions of the furnish, one of the portions having a compression wood/normal wood ratio of 75/25, and the other having a ratio of 10/90. Surface absorption and surface roughness were determined according to (EN 382-1) and (ISO 4287), respectively. It was found that panels made from furnish with a 75/25 ratio had a significantly lower surface absorption value (255.78 mm) than panels made from furnish with a 10/90 ratio (317.95 mm). Surface roughness measurements based on three roughness parameters, average roughness (Ra), mean peak-to-valley height (Rz), and maximum peak-to-valley height (Ry) were considered to evaluate the surface characteristics of the panels and supported the above findings as the panels made from furnish with a 75/25 ratio had slightly rougher surface with average values of 4.15 µm (Ra). From the tests performed, we conclude that increasing of the compression wood portion increased the surface roughness and decreased the surface absorption value.

• Akbulut, Istanbul University, Faculty of Forestry, Bahcekoy, TR-34473 Istanbul, Turkey E-mail: ta@nn.tr
• Ayrilmis, Istanbul University, Faculty of Forestry, Bahcekoy, TR-34473 Istanbul, Turkey E-mail: nadiray@istanbul.edu.tr

The management of low-volume roads has transitioned from focusing on maintenance designed to protect a capital investment in road infrastructure to also include environmental effects. In this study, two models using mathematical programming are applied to schedule forest road maintenance and upgrade activities involving non-monetary benefits. Model I uses a linear objective function formulation that maximizes benefit subject to budgetary constraints. Model II uses a non-linear objective function to maximize the sum of benefits divided by the sum of all costs in a period. Because of the non-linearity of the constraints and the requirements that the decision variables be binary, the solutions to both problem formulations are found using two heuristics, simulated annealing and threshold accepting. Simulated annealing was found to produce superior solutions as compared to threshold accepting. The potential benefit for completing a given road maintenance or upgrade project is determined using the Analytic Hierarchy Process (AHP), a multi-criterion decision analysis technique. This measure of benefit is combined with the economic cost of completing a given project to schedule maintenance and upgrade activities for 225 km (140 miles) of road in forested road systems within western Oregon. This combination of heuristics, cost-benefit analysis, environmental impacts, and expert judgment produces a road management schedule that better fits the current road management paradigm.

• Coulter, College of Forestry and Conservation, University of Montana, 32 Campus Drive, Missoula, MT 59812, USA E-mail: elizabeth.coulter@cfc.umt.edu
• Sessions, Department of Forest Engineering, College of Forestry, Oregon State University, 204 Peavy Hall, Corvallis, OR 97331-5706, USA E-mail: js@nn.us
• Wing, Department of Forest Engineering, College of Forestry, Oregon State University, 204 Peavy Hall, Corvallis, OR 97331-5706, USA E-mail: mgw@nn.us

The aim of this paper is to investigate different mathematical approaches to buck-to-order log merchandizing. A new bucking-to-order planning model using mixed integer programming was developed to determine the optimal production from a stand given different market constraints and forest inventory data. Three different approaches: market prices, target cutting patterns and adjusted price list were tested for generating cutting instructions to fulfill the plan created by the new planning model. The three approaches were evaluated in four test stands. The market prices approach simply applied the market prices to each stand. The target cutting patterns approach applied the sample cutting patterns generated from the planning model to the stand. The adjusted price list used a dynamic programming algorithm embedded in a search heuristic to adjust both the prices and small end diameters of log products to achieve the production goals of the planning models. The results showed that developing a buck-to-order plan is important in obtaining good order fulfillment. The target cutting patterns and adjusted price list approaches certainly out performed the market prices approach. This paper shows that these two approaches are capable of achieving excellent order fulfillment. Further development and testing is needed to determine which method is the best at generating cutting instructions for buck-to-order merchandizing.

• Marshall, Ensis Forests, Private Bag 3020, Rotorua, New Zealand E-mail: hamish.marshall@ensisjv.com
• Murphy, Forest Engineering Department, Oregon State University, Corvallis, Oregon 97331, USA E-mail: gm@nn.us
• Boston, Forest Engineering Department, Oregon State University, Corvallis, Oregon 97331, USA E-mail: kb@nn.us

Reconstructing three-dimensional structural changes in the forest over time is possible using archived aerial photographs and photogrammetric techniques, which have recently been introduced to a larger audience with the advent of digital photogrammetry. This paper explores the feasibility of constructing an accurate time-series of archived aerial photographs spanning 42 years using different types of geometric data and estimation methods for image orientation. A recent airborne laser scanning (lidar) data set was combined with the image block and assessed for geometric match. The results suggest that it is possible to establish the multitemporal geometry of an image block to an accuracy that is better than 0.5 m in 3D and constant over time. Even geodetic ground control points can be omitted from the estimation if the most recent images have accurate direct sensor orientation, which is becoming a standard technique in aerial photography. This greatly reduces the costs and facilitates the work. An accurate multitemporal image block combined with recent lidar scanning for the estimation of topography allows accurate monitoring and retrospective analysis of forest vegetation and management operations.

• Korpela, Department of Forest Resource Management, P.O. Box 27, FI-00014 University of Helsinki, Finland E-mail: ilkka.korpela@helsinki.fi

In many studies, adaptive cluster sampling (ACS) proved to be a powerful tool for assessing rare clustered populations that are difficult to estimate by means of conventional sampling methods. During 2002 and 2003, severe drought-caused damage was observed in the park forests of the City of Helsinki, Finland, especially in barren site pine and spruce stands. The aim of the present study was to examine sampling and measurement methods for assessing drought damage by analysing the effectiveness of ACS compared with simple random sampling (SRS). Horvitz-Thompson and Hansen-Hurwitz estimators of the ACS method were used for estimating the population mean and variance of the variable of interest. ACS was considerably more effective than SRS in assessing rare clustered populations such as those resulting from drought damage. The variances in the ACS methods were significantly smaller and the inventory efficiency in the field better than in SRS.

• Talvitie, University of Helsinki, Department of Forest Resource Management, P.O. Box 27, FI-00014 University of Helsinki, Finland E-mail: mervi.talvitie@helsinki.fi
• Leino, University of Helsinki, Department of Forest Resource Management, P.O. Box 27, FI-00014 University of Helsinki, Finland E-mail: ol@nn.fi
• Holopainen, University of Helsinki, Department of Forest Resource Management, P.O. Box 27, FI-00014 University of Helsinki, Finland E-mail: ah@nn.fi

The impacts of thinning at various intensities on the growth and mortality of mixed spruce-birch stands were investigated in thinning experiments on spruce swamps in northern and south-eastern Finland. At the time of establishment, three of the stands had recently reached the first commercial thinning stage and four were more advanced. The monitoring period was mainly 15 years, and the thinning intensity varied from heavy thinning (ca. 46 per cent of the basal area removed) to no thinning. Basal area removals of light and moderate thinning were ca. 22% and 39%, respectively. Unthinned plots had the highest volume increment. Light and moderate thinning slightly decreased the 15-year volume increment by, on an average, 1% and 8%, respectively. Heavy thinning led to a greater reduction (22%) in volume increment. The growth response to thinning intensity was evident as a higher relative volume and mean diameter increment of the living trees with decreasing stand density. Part of the volume increment on the unthinned plots was lost through natural mortality. Even light thinning significantly decreased natural mortality.

• Repola, Finnish Forest Research Institute, Rovaniemi Research Unit, P.O. Box 16, FI-96301 Rovaniemi, Finland E-mail: jaakko.repola@metla.fi
• Hökkä, Finnish Forest Research Institute, Rovaniemi Research Unit, P.O. Box 16, FI-96301 Rovaniemi, Finland E-mail: hh@nn.fi
• Penttilä, Finnish Forest Research Institute, Rovaniemi Research Unit, P.O. Box 16, FI-96301 Rovaniemi, Finland E-mail: tp@nn.fi

• Hotanen, Finnish Forest Research Institute, Joensuu Research Unit, P.O. Box 68, FI-80101 Joensuu, Finland E-mail: juha-pekka.hotanen@metla.fi
• Maltamo, University of Joensuu, Faculty of Forestry, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: mm@nn.fi
• Reinikainen, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland E-mail: ar@nn.fi

In order to understand the processes of snow and wind induced damage in a natural montane, secondary forest in northeastern China, we examined the impacts of site conditions on the snow and wind damage; analyzed if the dominant tree species differed in their susceptibilities to the damage; and established the relationships between the characteristics of tree and stand and the damage. The results indicated that in regard to the topography factors, slope steepness and soil depth played a relatively important role for the damage. Damage ratios of all types combined were positively related with the composition of dominant tree species. The stand density was also important in determining resistance to the damage, i.e., the densely populated stand exhibited less overall damage ratios; however, the dominant tree species were commonly damaged easily by the snow and wind. Four damage modes found (uprooting, stem breakage, canopy damage and bending) were closely related to the stem taper (p < 0.05), and they could be ranked in following order: bending (92.0 ) > uprooting (85.3) > stem breakage (80.1) > canopy damage (65.0). In regard to differences in tree species’ susceptibilities to the damage, Betula costata exhibited the most uprooting, bending and overall damage ratios; while Quercus mongolica showed the highest breakage (both stem breakage and canopy damage) ratio, and Fraxinus mandshurica exhibited the least damage ratio (overall). The major six tree species could also be divided into two groups according to the overall damage ratios, i.e., more susceptible ones (B. costata, Ulmus laciniata and Q. mongolica), and less susceptible ones (F. mandshurica, Acer mono and Juglans mandshurica) to the snow and wind damage.

• Zhu, Institute of Applied Ecology, Chinese Academy of Sciences, Wenhua Road 72, Shenyang 110016, China E-mail: zrms29@yahoo.com
• Li, Institute of Applied Ecology, Chinese Academy of Sciences, Wenhua Road 72, Shenyang 110016, China; Graduate School of Chinese Academy of Sciences, Yuquan Road 19-A, Beijing, 100039, China E-mail: xfl@nn.cn
• Liu, Institute of Applied Ecology, Chinese Academy of Sciences, Wenhua Road 72, Shenyang 110016, China; Graduate School of Chinese Academy of Sciences, Yuquan Road 19-A, Beijing, 100039, China E-mail: zgl@nn.cn
• Cao, Institute of Applied Ecology, Chinese Academy of Sciences, Wenhua Road 72, Shenyang 110016, China E-mail: wc@nn.cn
• Gonda, Faculty of Agriculture, Niigata University, Ikarashi 2-8050, Niigata, 950-2181, Japan E-mail: yg@nn.jp
• Matsuzaki, Faculty of Agriculture, Niigata University, Ikarashi 2-8050, Niigata, 950-2181, Japan E-mail: tm@nn.jp

Concerns about decline in soil fertility and long-term productivity of fast-growing plantations have promoted interest in using nitrogen-fixing trees in mixed species plantations. Populus deltoides and Alnus subcordata were planted in five proportions (100P, 67P:33A, 50P:50A, 33P:67A, 100A) in Noor, Iran. After 7 years, the effects of species interactions on tree growth and nutrient concentration in live and senescent leaves and soil properties were assessed. Diameter at breast height and total height of individual Populus trees were positively affected by the presence of Alnus. Nitrogen concentrations in fully expanded and senescent leaves of Populus were higher in mixed plantations than monoculture plantations. The results of nutrition and nutrient return and growth indicated that mixed plantations of these two species were more productive and sustainable than their monoculture plantations. Within the framework of this experiment, it appeared that production was maximized when these two species were grown together in the relative proportions of 50% Populus and 50% Alnus.

• Sayyad, Tarbiat Modarres University, Natural Resources Faculty, Emam St. Noor, 46414 Noor, Mazandaran, Iran E-mail: es@nn.ir
• Hosseini, Tarbiat Modarres University, Natural Resources Faculty, Emam St. Noor, 46414 Noor, Mazandaran, Iran E-mail: hosseini@europe.com
• Mokhtari, Tarbiat Modarres University, Natural Resources Faculty, Emam St. Noor, 46414 Noor, Mazandaran, Iran E-mail: jm@nn.ir
• Mahdavi, Tarbiat Modarres University, Natural Resources Faculty, Emam St. Noor, 46414 Noor, Mazandaran, Iran E-mail: rm@nn.ir
• Jalali, Tarbiat Modarres University, Natural Resources Faculty, Emam St. Noor, 46414 Noor, Mazandaran, Iran E-mail: sgj@nn.ir
• Akbarinia, Tarbiat Modarres University, Natural Resources Faculty, Emam St. Noor, 46414 Noor, Mazandaran, Iran E-mail: ma@nn.ir
• Tabari, Tarbiat Modarres University, Natural Resources Faculty, Emam St. Noor, 46414 Noor, Mazandaran, Iran E-mail: mt@nn.ir

First, second and third year needles were collected from the same branches of young Scots pine trees growing on soils of two different status (high and low fertility sites) that varied in mineral nutrient concentrations and N mineralisation potential. All needle age classes were analysed for total carbon, acid detergent fibre (ADF), lignin, cellulose, phenylpropanoid derivatives (PPD) of lignin, sugar constituents of non-crystalline, hydrated cellulose and hemicellulose, and nutrient concentrations (N, P, K, Ca, Mg and Mn). Significant intra-specific variation in the litter quality variables in relation to soils of high and low fertility was found in the second and third year needles, whereas there were no differences in the other cell wall constituents and mineral elements of the first year needles. The second and third year needles from the low fertility soil contained higher concentrations of ADF, lignin, cellulose, sugar constituents of non-crystalline, hydrated cellulose and hemicellulose, and phenylpropanoid derivatives (PPD) of lignin, but lower concentrations of N, P and Mg than the same needles from the high fertility and fertilised soils. The results in the present study indicate that under different soil fertilities, needle age classes show significant variations in the cell wall constituents and mineral elements, and suggest that this can result in significant variation in litter quality and decomposition rates.

• Sariyildiz, Kars Kafkas Üniversitesi, Artvin Orman Fakültesi, 08000 Artvin, Turkey E-mail: t_sariyildiz@yahoo.com
• Anderson, Department of Biological Sciences, Hatherly Laboratories, University of Exeter, Exeter EX4 4PS, UK E-mail: jma@nn.uk

Quercus aquifolioides Rehder & E.H. Wilson, an evergreen alpine and subalpine shrub species, occupies a wide range of habitats on the eastern slopes of the Himalaya in China. In this study, we measured leaf morphology, nitrogen content and carbon isotope composition (as an indicator of water use efficiency) of Q. aquifolioides along an altitudinal gradient. We found that these leaf morphological and physiological responses to altitudinal gradients were non-linear with increasing altitude. Specific leaf area, stomatal length and index increased with increasing altitude below 2800 m, but decreased with increasing altitude above 2800 m. In contrast, leaf nitrogen content per unit area and carbon isotope composition showed opposite change patterns. Specific leaf area seemed to be the most important parameter that determined the carbon isotope composition along the altitudinal gradient. Our results suggest that near 2800 m in altitude could be the optimum zone for growth and development of Q. aquifolioides, and highlight the importance of the influence of altitude in research on plant physiological ecology.

• Li, Chengdu Institute of Biology, Chinese Academy of Sciences, P.O. Box 416, Chengdu 610041, P. R. China E-mail: licy@cib.ac.cn
• Zhang, Chengdu Institute of Biology, Chinese Academy of Sciences, P.O. Box 416, Chengdu 610041, P. R. China; Graduate School of the Chinese Academy of Sciences, Beijing 100039, P.R. China E-mail: xz@nn.cn
• Liu, Sichuan Academy of Forestry, Chengdu 610081, P. R. China E-mail: xl@nn.cn
• Luukkanen, Viikki Tropical Resources Institute, P.O. Box 27, FI-00014 University of Helsinki, Finland E-mail: ol@nn.fi
• Berninger, Département des sciences biologiques, Cp 8888 succ centre ville, Université du Québec à Montréal, Montréal (QC) H3C 3P8, Canada E-mail: fb@nn.ca