Tree Resources Research Articles

Economics of Homestead Forestry and Their Management Activities at Fatickchari Upazila of Chittagong District, Bangladesh

An exploratory study was carried out to identify the homestead tree resources, their utilization pattern, economic return of major fruit and timber tree species, their management activities for sustainable production as well as constraints of homestead plantation in Fatickchari upazila of Chittagong district, Bangladesh over the period of six months by using multistage random sampling design of 96 households categorized into marginal (>0.02-0.08 ha), small (0.08-0.14 ha), medium (>0.14-0.20 ha) and large (>0.20 ha) based on homestead areas. Sample households were selected randomly taking three from each category in each ward. Total number of tree species was increased with the increase in homestead areas. In case of socio-economic aspects of the respondents, it was found that tree variety (%) has a gradual increasing trend with increase of education level. However, relative tree density (%) was found to have increasing trend with education up to higher secondary level and after that there was a slight decreasing trend. People involve in agriculture have got higher tree density (31%) compared to other occupations such as; service (28%), business (24%) and daily labour (17%). The investment analysis revealed that longer time investment on fruit and timber tree species is profitable. Lack of technical knowledge of growing trees, unavailability of space and good quality seed/seedlings were the major constraints of homestead forestry production. This study may be useful baseline information to forest policy makers in Bangladesh.

Competition response of European beechFagus sylvaticaL. varies with tree size and abiotic stress: minimizing anthropogenic disturbances in forests

SummaryNew forest management approaches aim to ensure high biodiversity and climatic adaptability. Silvicultural practices can alter tree–tree interactions and thus influence forest structure and composition. However, knowledge of the interacting effects of competitive and abiotic stress in tree communities is still limited.We assessed growth dynamics of European beechFagus sylvaticain oligo‐ to eutrophic lowland beech forests by quantifying variation in the importance and intensity of competitive interactions among adult trees along a productivity gradient defined by nutrient availability and hydrological characteristics. We further predicted changes in competition indices with various levels of crowding for different forest types. Basal area growth of 1819 canopy trees was analysed using forest inventory data.Competition response of adult trees was inconsistent among forest types. For small timber trees, the intensity (absolute effect) and importance (effect relative to abiotic constraints) of competition decreased with increasing abiotic stress. Growth responses of medium and large timber trees, however, revealed an opposite trend. Thus, in tree communities, competition effects did not follow a general pattern, because tree maturation altered the responsiveness of trees to environmental stress.Resource dependency of competition effects was most pronounced for large timber trees, with lowest sensitivity to changes in crowding conditions occurring on fertile sites. For small and medium timber trees, however, competition effects were strongest in dense stands, with lowest sensitivity to changes in crowding conditions on resource‐limited sites.Synthesis and applications. Tree–tree interactions in beech forests showed a clear pattern which depended on tree maturation and resource supply. This highlights the importance of considering tree size‐related changes along environmental gradients in regional growth models. Our findings indicate that management practices could facilitate both timber production and nature conservation demands by adapting thinning approaches to age‐ and resource‐related tree growth patterns. We propose a distinct reduction in thinning intensity, particularly for larger beech trees growing on sites with optimum below‐ground resources. This would increase the permanent stand volumes and promote natural stand dynamics, which in turn would benefit biodiversity typical of old‐growth beech forest ecosystems.

Adaptive genetic diversity of trees for forest conservation in a future climate: a case study on Norway spruce in Austria

Genetic resources of forest trees are considered as a key factor for the persistence of forest ecosystems because the ability of tree species to survive under changing climate depends strongly on their intraspecific variation in climate response. Therefore, utilizing available genetic variation in climate response and planting alternative provenances suitable for future climatic conditions is considered as an important adaptation measure for forestry. On the other hand, the distribution of adaptive genetic diversity of many tree species is still unknown and the predicted shift of ecological zones and species’ distribution may threaten forest genetic resources that are important for adaptation. Here, we use Norway spruce in Austria as a case study to demonstrate the genetic variation in climate response and to analyse the existing network of genetic conservation units for its effectiveness to safeguard the hotspots of adaptive and neutral genetic diversity of this species. An analysis of the climate response of 480 provenances, clustered into 9 groups of climatically similar provenances, revealed high variation among provenance groups. The most productive and promising provenance clusters for future climates originate from three regions that today depict the warmest and driest areas of the natural spruce distribution in Austria. Gap analysis of the Austrian genetic conservation units in the EUFGIS Portal suggests adequate coverage of the genetic hotspots in southern parts of Austria, but not in eastern and northern Austria. Therefore conservation measures and sustainable utilization of the valuable genetic resources in these regions need to be expanded to cover their high adaptive genetic variation and local adaptation to a warmer climate. The study shows that current conservation efforts need to be evaluated for their effectiveness to protect genetic resources that are important for the survival of trees in a future climate.

Tropical tree growth is correlated with soil phosphorus, potassium, and calcium, though not for legumes

Tropical forest productivity is widely assumed to be limited by soil phosphorus (P), but biogeochemical processes that deplete P also could deplete base cations, suggesting multiple resource limitation. Limitation by several resources could arise from species and functional diversity and from variation among groups in resource requirements, including ecophysiological strategies that minimize P limitation. We hypothesized that tree growth is positively related to soil base cation and P availability and negatively related to local competition; Fabaceae growth is weakly correlated with soil resources if fixed N is used indirectly to acquire other resources; growth of species with low wood density is more strongly related to soil resource availability than that of species with high wood density. Diameter growth and soil resource availability were measured in five mapped stands situated across natural soil resource gradients in lowland wet tropical forest (La Selva Biological Station, Costa Rica). Soil resource availability, and associated uncertainty, was estimated for each tree using a Bayesian multivariate spatial regression model, with individual tree growth being a function of diameter, local neighborhood, and soil resources. Separately, site‐level mean tree growth and resource availability were modeled using linear regression. Individual diameter growth and site mean basal area increment correlated with soil base cations and P, but rarely with N; individual growth correlated negatively with neighborhood index for only three species. Growth of Fabaceae was unrelated to soil resources at both individual and site levels. When species were categorized by wood density, growth was related to soil P or base cation availability, with the strongest correlation between the lowest‐density species and soil P. Several resources may limit tropical forest productivity, because tree growth was similarly correlated with soil P and base cations, but functional groups responded differently. Negligible growth relationships with soil resources in Fabaceae suggest that N fixation may alleviate mineral nutrient limitations. Correlations of soil P with growth of species of low wood density and base cations with species of higher density suggests variation in resource demands among functional groups. Thus, tropical tree growth may be limited by base cations and/or P, with degree and type of resource limitation dependent on functional or taxonomic group.

The genomes of the giants: a walk through the forest of tree genomes

Tree genome issue: Title: The genomes of the giants: a walk through the forest of tree genomes Preface: Arguably, trees are the most important plant species contributing to the direct success of the human endeavor and represent cornerstone species for the future of sustainable local agriculture due to their highly favorable balance of input (tilling requirements, water, fertilizers, pest control) to output (yields) in contrast to many other commodity crops. Trees or tree products are utilized in almost every application directly relevant to human survival. Their fruits provide key components to the human diet, their trunks and limbs serve to provide energy for heating and materials for building, their leaves provide cover and shading to the underlying earth while capturing and storing significant amounts of atmospheric carbon, and their decay products contribute to the health of the complex biological web of forest ecosystems and the biosphere. Surprisingly, however, our understanding of the intricate relationship between the characters important to the utilization and sustainability of trees and the underlying genetic composition of these characters is still in its infancy. However, in recent years, we have experienced a substantial change in the attitudes of both public and private funding sources coupled with advances in genomics technologies that have directly contributed to setting the stage for the unprecedented discovery of the underlying genetic nature of many important tree traits. This remarkable turn of events is now providing us with clues to the underlying organization and evolution of tree genomes, and this knowledge is driving the development of new breeding strategies to improve and sustain our fruit tree and forest tree resources. This special issue of TreeGenetics andGenomes is devoted to showcasing examples of the state of our knowledge of the organization and expression of particular tree genomes that are serving as models for genetics research in their respective plant families and in other plant families as well. Our intent is to provide an overview of what resources are available; what resources are currently being produced, and how these resources are contributing to our fundamental understanding of plant biology. Perhaps Robert Frost stated our current situation best when he wrote, “The woods are lovely, dark and deep, but I have promises to keep, and miles to go before I sleep, and miles to go before I sleep.” Our work on tree genomes is just beginning, and we still have a longway to go in understanding the biological nature and importance of these very special giants; however, what we have from this very initial glimpse is certainly lovely dark and deep.

From Farmers to Loggers: The Role of Shifting Cultivation Landscapes in Timber Production in Cameroon

This article focuses on timber sourced from the agricultural areas in the shifting cultivation landscapes of the Central Region of Cameroon. Data about volumes marketed in urban centres, harvesting operations and on-farm timber management are used to discuss the ecological impact of small-scale logging and its sustainability in the long term. An opportunistic association exists between small-scale logging and agricultural land uses, determined mostly by the abundance of valuable species in fallows and on cocoa farms, their easy accessibility and the low price of farmland timber. Farmers apply various strategies to the management of tree resources in fallows and cocoa agroforests, with most felling authorized in fallows and most trees preserved on the cocoa farms. With current agricultural expansion and intensification trends associated with small-scale logging, timber resources on rural land are at risk of depletion with direct consequences for domestic timber supply and the thousands of livelihoods it sustains. Marketing and regulatory changes are needed to encourage the integration of timber production in agricultural management systems.

Delay-constrained survivable multicast routing problem in WDM networks

In WDM network, link failure may cause service disruption and may lead to lose significant information. Especially, for a multicast transmission when link on a light-tree that carries traffic to multiple destinations failed, the traffic to all the downstream destinations along the failed link will be affected. For a given multicast request with a maximum delay denoted as Δ, the delay-constrained survivable multicast mechanism provides the primary multicast tree and some sparse resources to protect it. When link failure occurred, the multicast transmission is recovered by using sparse resources while ensuring that the backup tree can satisfy the delay constraint. This problem is called Delay-Constrained Survivable Multicast Routing Problem (DCSMRP). In this article, three protection methods are used to solve this problem; they are: Delay Constrained Link-disjoint Tree Protection (DCLTP), Delay Constrained Disjoint-Paths Protection (DCDPP) and Delay Constrained Span p-Cycle Protection (DCSP). Three multicast routing methods are proposed for the respective protecting methods to find the primary multicast tree and backup resources with delay constraint. Experiments are conducted to evaluate the resource utility ratio (RUR), blocking ratio (BR) and executing time (RT) of these methods. Simulations show that the DCSP method can get best BR for the cases with greater delay bound (for the cases with delay bound Δ>5.5ms.) The RUR of DCSP is worse than that of DCLTP and DCDPP (in the cases with delay bound Δ⩾7.5msec), and the computational time of the DCDPP is faster than that of the DCSP and DCLTP.

Leaf area and light use efficiency patterns of Norway spruce under different thinning regimes and age classes

Silviculture focuses on establishing forest stand conditions that improve the stand increment. Knowledge about the efficiency of an individual tree is essential to be able to establish stand structures that increase tree resource use efficiency and stand level production. Efficiency is often expressed as stem growth per unit leaf area (leaf area efficiency), or per unit of light absorbed (light use efficiency). We tested the hypotheses that: (1) volume increment relates more closely with crown light absorption than leaf area, since one unit of leaf area can receive different amounts of light due to competition with neighboring trees and self-shading, (2) dominant trees use light more efficiently than suppressed trees and (3) thinning increases the efficiency of light use by residual trees, partially accounting for commonly observed increases in post-thinning growth. We investigated eight even-aged Norway spruce (Picea abies (L.) Karst.) stands at Bärnkopf, Austria, spanning three age classes (mature, immature and pole-stage) and two thinning regimes (thinned and unthinned). Individual leaf area was calculated with allometric equations and absorbed photosynthetically active radiation was estimated for each tree using the three-dimensional crown model Maestra. Absorbed photosynthetically active radiation was only a slightly better predictor of volume increment than leaf area. Light use efficiency increased with increasing tree size in all stands, supporting the second hypothesis. At a given tree size, trees from the unthinned plots were more efficient, however, due to generally larger tree sizes in the thinned stands, an average tree from the thinned treatment was superior (not congruent in all plots, thus only partly supporting the third hypothesis).

DIVERSITY AND DYNAMICS OF MANAGEMENT OF GUM AND RESIN RESOURCES IN ETHIOPIA: A TRADE‐OFF BETWEEN DOMESTICATION AND DEGRADATION

ABSTRACTAlthough the human domestication of forest and tree resources is often considered to result in resource degradation, it may also lead to improved resource potentials. This paper assesses the nature and dynamics of gum and resin focused woodland exploitation and management systems in Ethiopia in the context of degradation and domestication processes. In three sites with commercial gum resin producing woodlands and production history, we studied variation in (i) woodland management and gum resin production systems and (ii) socio‐economic and biophysical factors that condition the management and production systems. On the basis of their organizational features, we formulated nine production models and related them to different phases of domestication and different degrees of ecosystem degradation. The production systems gradually evolved from the extraction of wild trees to production in an adapted forest system. However, domesticated woodlands with an adapted forest structure and composition and increased provisioning services are still little developed despite decades of production history. Many of these woodlands are undergoing serious degradation because of low quality management practices. This is mainly attributable to existing land use practices and the social arrangements for the production of and trade in the gums and resins. The findings illustrate that domestication involves not only a change in ecological and production systems but also the development of social arrangements for production and trade. We conclude that the status of domestication in a social sense determines whether forests and/or specific forest resources are degraded or aggraded in the sense of resource enrichment. Copyright © 2011 John Wiley & Sons, Ltd.

A drought stress transcriptome profiling as the first genomic resource for white teak - Gamhar - (Gmelina arborea Roxb) and related species

Background Gmelina (Gmelina arborea Roxb), also known as white teak is a tropical deciduous tree native from moist tropical forests of Asia. It has been successfully introduced in equatorial Africa, as well as central and south America. Gmelina is known for its very fast growing rate, its intrinsic disease, fire and drought tolerance, as well as the quality of its wood which is suitable for different types of uses such as paper pulping, plywood or particle board industry, furniture and light constructions. In addition, gmelina is considered a pioneer plant species capable of rapidly colonizing eroded or low nutritional quality lands, which makes it interesting for reforestation or landscape restoration programs. Despite its ecological and increasing economic importance, very little is known about the biology of this species and its remarkable field behavior such as drought tolerance, at the genetic, molecular and biochemical levels. Genomic tools have recently increased the numbers and volume of genomic resources for several crop plants and trees and have contributed to enlarge our knowledge on basic aspects of plant biology, population dynamics or phylogeny; furthermore, they represent valuable sources of candidate genes and new molecular markers to assist breeding programs. Biological sequences reported to date in public databases and belonging to Gmelina do not exceed 20 entries: this very narrow availability of genetic information is the main bottleneck to initiate molecular breeding programs in Gmelina arborea. We report here the first genomic resource for this tropical tree based on an RNAseq transcriptome profiling approach.

Die Baumbedeckung in der Schweiz

Tree cover in Switzerland The requirements for national forest inventories have changed in recent decades, as have the issues involved. Initially, the focus was mainly information on timber resources, but today social and environmental functions are also of interest. An a priori separation of the surveyed areas into forest and non-forest during data collection limits the interpretation of the tree resources. Not all trees are located in the forest and not all forests are fully stocked. In the aerial photo interpretation of the 3rd National Forest Inventory, land cover on a regular sampling grid was determined regardless of the land use. This allowed, for the first time, nationwide information on tree resources to be obtained, independent of forest definitions. The tree cover of Switzerland is 27.0% regardless of whether the trees are in the forest or outside. The area covered with forest (proportionally 29.4%) is larger than that covered with trees. The location of the trees outside the forest tends to be mostly either very close to forest or in urban areas. The most densely stocked areas, after forests, are urban areas. The data from aerial photo interpretations of the 3rd National Forest Inventory allow a more nuanced picture of the stocking over the whole country, but the sampling error is still too large to draw conclusions for small areas. The existing and ongoing surveys, however, provide a calibration and reference dataset so that, with remote sensing data and methods, it should be possible to generate more comprehensive spatial datasets to help to fill this gap.

A national level forest resource assessment for Burkina Faso – A field based forest inventory in a semiarid environment combining small sample size with large observation plots

Even though considerable parts of the global tropical forests are located in Africa, reliable data on African forest resources is limited. While this is widely recognized for tropical moist forests, it also holds for tropical dry forests. To partially fill the gap a forest inventory was carried out in Burkina Faso, West Africa. In this paper we present a methodological approach and sample based estimates of the tree and forest resources including estimates of (1) land cover classes, (2) species composition, and (3) above ground tree carbon stocks. Following the land classification of the Food and Agriculture Organization of the United Nations (FAO), the forest cover of Burkina Faso was estimated as 42.6% (116,847 km 2). For the classes “other wooded land”, “other land” and “other land with tree cover” the estimates were 1.6%, 53.6%, and 9.1%, respectively. We found notable differences to the estimates published by FAO, in particular when considering the classes “forest” and “other wooded land” separately, but lesser so when the two classes are combined. That points to a major issue in applying these class definitions in semiarid environments. Given the relatively small sample size ( n = 46 field observed plots), relative standard errors (SE%) of area estimates are high (around 9% for the larger area classes). Aboveground tree carbon stocks were estimated to be 6.640, 5.580 and 7.222 Mg ha −1 for “forest”, “other wooded land” and “other land with tree cover”, respectively (SE% around 18% for all three estimates). Availability of biomass models is very limited for all classes, in particular when it comes to shrubs. Furthermore, it was estimated that the most abundant tree species in Burkina Faso is Vittelaria paradoxa, the “shea butter tree” which is a multi-use tree species of high relevance for rural livelihoods. To our knowledge this study is the first field-based forest inventory on national level in Burkina Faso where the estimation of errors was possible on statistical grounds, and done. The results of this study revealed major issues that should be taken into account when doing similar studies, including carbon monitoring and accounting: increasing the sample size will lead to smaller standard errors (at a higher costs, of course), but will not solve the crucial points (1) of non-availability of suitable biomass models, in particular for shrub lands and (2) of implementation issues regarding the definition of land cover types.

M-Convex Function Minimization by Continuous Relaxation Approach: Proximity Theorem and Algorithm

The concept of M-convexity for functions in integer variables, introduced by Murota [Adv. Math., 124 (1996), pp. 272–311], plays a primary role in the theory of discrete convex analysis. In this paper, we consider the problem of minimizing an M-convex function, which is a natural generalization of the separable convex resource allocation problem under a submodular constraint and contains some classes of nonseparable convex function minimization on integer lattice points. We propose a new approach for M-convex function minimization based on continuous relaxation. By establishing proximity theorems we develop a new algorithm based on continuous relaxation. We apply the approach to some special cases of the separable convex quadratic resource allocation problem and the convex quadratic tree resource allocation problem to obtain faster algorithms.

Inventory methods for trees in nonforest areas in the great plains states

The US Forest Service's Forest Inventory and Analysis (FIA) program collects information on trees in areas that meet its definition of forest. However, the inventory excludes trees in areas that do not meet this definition, such as those found in urban areas, in isolated patches, in areas with sparse or predominantly herbaceous vegetation, in narrow strips (e.g., shelterbelts), or in riparian areas. In the Great Plains States, little is known about the tree resource in these noninventoried, nonforest areas, and there is a great deal of concern about the potential impact of invasive pests, such as the emerald ash borer. To address this knowledge gap, FIA's National Inventory and Monitoring Applications Center has partnered with state cooperators and others in a project called the Great Plains Initiative to design and implement an inventory of trees in nonforest areas. The goal of the inventory is to characterize the nonforest tree resource using methods compatible with those of FIA so a holistic understanding of the resource can be obtained by integrating the two surveys. The goal of this paper is to describe the process of designing and implementing the survey, including plot and sample design, and to present some example results from a reporting tool we developed.

DIVERZITET, STRUKTURA I TEKSTURA PRAŠUME I GOSPODARSKE ŠUME BUKVE I JELE SA SMRČOM NA GRMEČU U ZAPADNOJ BOSNI

UDK 630*2:630*4/.5(253)(497.6 Grmeč)
 The research of the diversity, structure and texture was performed on the mountain Grmeè in western Bosnia, in the summer and fall of 2007, in the virgin forest and in the managed forest of beech and fir with spruce. For the research purposes, a systematic network of experimental circles within the distance of 1 x 1 km was installed in the managed forest. On the intersection of the squares network, 14 circular surfaces of 25 m radius were installed. All circular surfaces were placed in different sections. In the virgin forest a permanent experimental surface of size 100 x 100 m was set, with surface of 1 ha and one circular surface of radius 25 m, with surface of 1963 m2. The research determined the horizontal (opposing) and vertical structure, the diversity, the quality of the resources and the health of the virgin forest plus the managed forest. The texture was determined only for the virgin forest. The diversity of the tree types over the number of trunks in the virgin forest is 1,79, in the managed forest 1,78, over the basal; these indexes for the virgin forest are 1,24 and for the managed forest 1,64. The virgin forest has a poorer structure of tree resources compared to the managed forest, but is of better health. In the managed forest there are many trunks of suspicious health, as much as 35,8 %. The texture diversity in the virgin forest is 2,43.

Short‐term Effects of Single Species Browsing Release by Different‐sized Herbivores on Sand Forest Vegetation Community, South Africa

ABSTRACTManipulations of herbivores in protected areas may have profound effects on ecosystems. We examine short‐term effects on tree species assemblages and resource utilization by a mesoherbivore and small‐size herbivores (ungulates <20 kg) in Sand Forest, after browsing release from a megaherbivore (elephant), or both a mega‐ and mesoherbivore (nyala), respectively. Effects were experimentally separated using replicated exclosures where all trees were counted, identified to species and browsing events recorded. Tree species assemblages were impacted by both elephant and nyala, and by each herbivore species individually. Tree turnover rates were higher where both herbivore species were present than in their combined absence. Diet was segregated among elephant, nyala and small‐size herbivores. Both resource specificity and browsing pressure by nyala increased in absence of elephant; small‐size herbivores increased resource specificity in absence of elephant, and increased browsing pressure in absence of both elephant and nyala. This implies interference competition with competitive release. The indirect effect of the manipulation of herbivore populations, through the removal of one or two herbivore species, caused a shift in tree species composition and diet of smaller‐size herbivores. These indirect effects, especially on tree species composition, can become critical as they affect vegetation dynamics, biodiversity and ecosystem processes. Therefore, in order to conserve habitats and biodiversity across all trophic levels, conservation managers should consider the effects of: (1) the full herbivore assemblage present; and (2) any effects of altering the relative and absolute abundance of different herbivore species on other herbivore species and vegetation.

Household decision-making in agroforestry parklands of Sudano-Sahelian Mali

This study examines farmers’ knowledge and management of soil fertility and vegetation in Vitellaria paradoxa and Cordyla pinnata dominated agroforestry parklands in a Sudano-Sahelian region of Mali. Qualitative data from a series of semi-structured interviews were used to construct an empirically based typology of farmer practices. These interrelated practices center on famers’ agroecological knowledge, decision-making, and cropping strategies and are conceptualized as variable and adjustable socioecological responses to environmental and socioeconomic contingencies. The typology categorizes farmers in terms of their capacity for managing parkland soil and tree resources in an ecologically sustainable manner while negotiating livelihood challenges. It identifies the ideal farmer as one who practices the following: (1) use of environmental knowledge that considers multidimensional relationships among ecological and social components of parkland systems, (2) agricultural techniques that adaptively combine aspects of intensive and traditional extensive agriculture, and (3) natural resource decision-making that explicitly includes women’s environmental knowledge and livelihood strategies.

Combining tree-ring analyses on stems and coarse roots to study the growth dynamics of forest trees: a case study on Norway spruce (Picea abies [L.] H. Karst)

We show the potential of a new method combining tree-ring analyses on stems and on coarse roots of individual trees in order to advance the understanding of growth dynamics in forest trees. To this end, we studied the root–shoot allometry of trees and its dependence on site conditions. Along a gradient in water supply in Southern Germany from dry to moist sites we selected 43 Norway spruce trees (Picea abies [L.] H. Karst.) aged 65–100 years. Increment cores were taken from stem and main roots revealing aboveground and belowground growth course over the last 34 years. Annual growth rates in roots and stems and their allometric relationships were applied as surrogate variables for tree resource allocation to aboveground and belowground organs. The mean sensitivities of both stem and root chronologies were found to be site-specific, and increased from the moist through the dry sites. No temporal offset between aboveground and belowground growth reactions to climate conditions was found in Norway spruce at any of the sites. These results suggest that the root–shoot allometry depends on the specific site conditions only at the driest site, following the optimal biomass partitioning theory (the more restricted the water supply, the more organic matter allocation into the belowground organs).

Benefits of a forested urban park: What is the value of Allan Gardens to the city of Toronto, Canada?

Treed urban parks provide numerous social, environmental, and economic services of measurable value to a city. To better understand the importance of a forested urban park we employ the Street Tree Resource Assessment Tool for Urban Forest Managers (STRATUM) to investigate the value of services provided by trees in Allan Gardens, a historic public park in downtown Toronto, Canada. A full inventory, conducted in 2008, found 309 trees representing 43 species. Park trees provided 26,326 USD in annual benefits ($16,665 environmental; $9661 aesthetic) during 2008, and delivered a benefit-to-cost ratio of 3.4:1. Tree size and leaf area are larger in Allan Gardens when compared with trees growing in other Toronto parks and across the city as a whole. The flow of benefits from Allan Gardens’ urban forest is heavily dependent upon Norway Maple ( Acer platanoides), a finding mirrored across much of Toronto's urban forest. Norway Maple provides the greatest overall annual benefits ($4846 total; $113 per tree) and as a species contributes 17.5% of the environmental and 20% of aesthetic value provided by trees in the park. This work offers a model to urban planners, providing a straightforward methodology for quantifying the value of nature in public city spaces, in the form of treed parks.

Performance of Forest Management Committees in Cross River State, Nigeria

Forest and tree resources are of extreme importance to mankind because they provide a wide variety of useful products that feature in our everyday lives. However, the forest estate of Nigeria is being depleted at an unsustainable annual rate of 3.5% and the Sahara Desert is encroaching southward by about one kilometre each year. The Nigerian state-led forest management structure has failed to check this trend; hence the introduction of forest management committees (FMCs), representing a participatory (including the government) forest management structure led by the owner community. This study examines the performance of FMCs in Cross River state. Information was obtained through oral interviews with officials and a questionnaire survey of other respondents. The results of the data analysis show that the intensity of forest management practices was significantly higher in communities with FMCs than in those without. In communities without FMCs, household income from forestry was derived mainly from timber products and was significantly higher than in communities with FMCs, where forestry income was mainly from non-wood forest products. This shows the level of forestry restriction and regulation obtainable in communities with FMCs. Among the factors identified as influencing respondents' perceptions about the use of FMCs, five were positive and statistically significant: age, level of education, level of household income from forestry, regular harvest of forest products and presence of an erosion problem in the community. The Likert scale rating of the constraints encountered by FMCs indicated that the most challenging of these were: lack of commitment of members, change in government policies, financial constraints, inter- and intra-community conflicts, inadequate support from community leadership and a negative attitude on the part of the community to forest conservation.