Restoring rainforest species by direct seeding: Tree seedling establishment and growth performance on degraded land in the wet tropics of Australia

The establishment and growth performance of directly seeded rainforest tree species on degraded sites was investigated in the wet tropical region of north east Queensland, Australia. Trials were established at three degraded sites previously covered by rainforest, using two different sowing times (the beginning and end of the wet season), and a range of species having different seed sizes and successional status. The results two years after sowing showed that the effects of sowing time on tree seedling establishment were small despite pronounced differences in cumulative rainfall received by the seedlings. Results suggested that at some sites more serious weed competition might be avoided by sowing later in the season. Although some small seeded early successional species could grow quickly, the establishment of these was found to be significantly negatively affected by the growth of weeds, and in most cases, large seeded species showed more consistent establishment. On the other hand the growth rates of larger seeded species were often rather slow, limiting their contribution to early site capture. Results indicate that direct seeding can be a viable establishment method, but the identity of species to be used, the circumstances under which they should be directly sown and the most appropriate timing of sowing will vary with situations. Species characteristics, including seed size, growth rate potential and light requirement will be important to consider in relation to the probable conditions that will develop for seedlings following germination (particularly in relation to plant competition) with or without post-sowing site management, such as removal of weeds.     

The tree planting and protecting culture of cattle ranchers and small-scale agriculturalists in rural Panama: Opportunities for reforestation and land restoration

To examine the opportunities available for designing diverse tree planting and land restoration initiatives in agricultural landscapes that contain tropical dry forests, the tree planting and protecting practices of cattle ranchers and small-scale agriculturalists were examined in two study sites in rural Panama. Ninety-nine tree species were identified that they utilize, plant, or protect on their land, the majority of which are native to Panama. The farmers had diverse reasons for maintaining trees, including improving the environment, providing food and shade for cattle, and generating a source of wood for construction, furniture, and firewood. Most of the trees mentioned in the study provide multiple uses and values and the majority of farmers wanted to plant additional trees. Some differences in species preferences and motivations for planting and protecting trees were seen between sites, thereby suggesting that land restoration and tree planting projects should be site specific. Our data indicate that there are ample opportunities to increase native tree cover in our study sites and highlight the need to incorporate farmer input into project design, implementation, and evaluation as a necessary and continuous feature throughout projects.     

Fire Ecology and Management in the La Amistad Biosphere Reserve,Panama

Abstract

The use of fire in the La Amistad Biosphere Reserve, Panama, is a complex issue, especially given its biophysical, cultural, and socioeconomic context. A geographic gradient exists, depicting the threat from fire to the reserve. Areas around Volcan Baru have a high potential fire threat due to the biophysical aspects of the area and land-use activities. Fire use has a long cultural history in Panama. It continues to be frequently employed to clear land for swidden agriculture, cattle ranching on the Atlantic side of the Talamancan mountain range, and agricultural development on the Pacific side. Land tenure insecurity and perverse policies also incite its utilization for claiming land. Set fires often escape their boundaries and burn property, structures, crops, and fire-sensitive ecosystems. If left unchecked, anthropogenic fires pose a significant threat to both the ecological and socioeconomic well being of the Biosphere Reserve. Recommendations for the reserve's fire management plan focus on policy augmentation, educational outreach, monitoring, prevention, and fire research.     

Inoculation with the ectomycorrhizal fungi <Emphasis Type="Italic">Pisolithus arhizus</Emphasis> and <Emphasis Type="Italic">Scleroderma</Emphasis> sp. improves early growth of <Emphasis Type="Italic">Shorea pinanga</Emphasis> nursery seedlings

Trees of the family Dipterocarpaceae are the dominant trees in Southeast Asian tropical forests where they play an important ecological role and are also important commercially. An experiment was conducted to determine the effect of ectomycorrhizal fungi on the growth of dipterocarp species in peat soils. Seedlings of Shorea pinanga were inoculated with spores of two ectomycorrhizal fungi, Pisolithus arhizus and Scleroderma sp. were grown in pots containing sterilized peat soil for 7 months. The percentage of ectomycorrhizal colonization on S. pinanga exceeded 86%. Colonization of S. pinanga roots by ectomycorrhizal fungi resulted in increased shoot height, stem diameter, number of leaves, and shoot fresh and dry weight. Survival rates of S. pinanga were greater for inoculated seedlings than control seedlings. These results suggest that inoculation of ectomycorrhizal fungi can improve the early growth of S. pinanga grown in tropical forests and that this technique will accelerate the rehabilitation of degraded dipterocarp forests.     

Tree seedling establishment in living fences: a low-cost agroforestry management practice for the tropics

Establishing trees in pastures can have production and conservation benefits, but is complicated by the presence of livestock. The need to protect seedlings from livestock increases tree establishment costs, which in turn, can deter landowners from planting trees. Living fences are a ubiquitous feature of pasture landscapes in the tropics that could help protect newly planted trees by preventing livestock trampling and browsing. This study quantified the effectiveness of a living fence in protecting tree seedlings during the first 2 years after planting. The four native tree species evaluated were: Cedrela odorata L., Pachira quinata (Jacq.) W.S. Alverson, Samanea saman (Jacq.) Merr., and Tabebuia rosea (Bertol.) A. DC. Results show that the living fence provided protection from livestock except in cases where tree species were highly palatable as forage (i.e. P. quinata). Trees planted into the living fence generally had greater survival (62 vs. 28%), relative growth (10.3 times initial height vs. 5.8 times initial height), and final height (191 cm vs. 108 cm) compared to those planted in open pasture after 2 years. However, survival and growth of trees planted into the fence remained lower than that observed at a nearby plantation with no livestock, regular weeding and no living fences. This study indicates that use of living fences as a protective barrier could be an effective low-cost approach for establishing trees in tropical pasture landscapes.

Forest structure and live aboveground biomass variation along an elevational gradient of tropical Atlantic moist forest (Brazil)

Live aboveground biomass (AGB) is an important source of uncertainty in the carbon balance from the tropical regions in part due scarcity of reliable estimates of live AGB and its variation across landscapes and forest types. Studies of forest structure and biomass stocks of Neotropical forests are biased toward Amazonian and Central American sites. In particular, standardized estimates of aboveground biomass stocks for the Brazilian Atlantic forest are rarely available. Notwithstanding the role of environmental variables that control the distribution and abundance of biomass in tropical lowland forests has been the subject of considerable research, the effect of short, steep elevational gradients on tropical forest structure and carbon dynamics is not well known. In order to evaluate forest structure and live AGB variation along an elevational gradient (0–1100 m a.s.l.) of coastal Atlantic Forest in SE Brazil, we carried out a standard census of woody stems ≥4.8 cm dbh in 13 1-ha permanent plots established on four different sites in 2006–2007. Live AGB ranged from 166.3 Mg ha⁻¹ (bootstrapped 95% CI: 144.4,187.0) to 283.2 Mg ha⁻¹ (bootstrapped 95% CI: 253.0,325.2) and increased with elevation. We found that local-scale topographic variation associated with elevation influences the distribution of trees >50 cm dbh and total live AGB. Across all elevations, we found more stems (64–75%) with limited crown illumination but the largest proportion of the live AGB (68–85%) was stored in stems with highly illuminated or fully exposed crowns. Topography, disturbance and associated changes in light and nutrient supply probably control biomass distribution along this short but representative elevational gradient. Our findings also showed that intact Atlantic forest sites stored substantial amounts of carbon aboveground. The live tree AGB of the stands was found to be lower than Central Amazonian forests, but within the range of Neotropical forests, in particular when compared to Central American forests. Our comparative data suggests that differences in live tree AGB among Neotropical forests are probably related to the heterogeneous distribution of large and medium-sized diameter trees within forests and how the live biomass is partitioned among those size classes, in accordance with general trends found by previous studies. In addition, the elevational variation in live AGB stocks suggests a large spatial variability over coastal Atlantic forests in Brazil, clearly indicating that it is important to consider regional differences in biomass stocks for evaluating the role of this threatened tropical biome in the global carbon cycle.     

Mineral Nutrition and Fertilization of Native Tree Species in Brazil

Abstract

In this review article, the progress of Brazilian research on mineral nutrition and fertilization of native tree species is discussed, taking as reference the scientific knowledge regarding the exotic species of the genera Eucalyptusand Pinus. There is a great knowledge gap in the theoretical base needed to develop technologies on nutritional management of native species. The high diversity of species, with variable or unknown responses to nutrient supply, makes difficult to set up a standardized and efficient fertilizer recommendation. Nevertheless, taking into account the successional groups and the growth rate of species, it is possible to discriminate the levels of nutritional requirements and to define differential management strategies of fertilization. Relevant aspects for future research on this line are also suggested.     

Compatibility of timber and non-timber forest product management in natural tropical forests: Perspectives,challenges, and opportunities

Tropical forests could satisfy multiple demands for goods and services both for present and future generations. Yet integrated approaches to natural forest management remain elusive across the tropics. In this paper we examine one combination of uses: selective harvesting of timber and non-timber forest product (NTFP) extraction. We analyze the current status of this combination and speculate on prospects and challenges regarding: (i) resource inventory, (ii) ecology and silviculture, (iii) conflict in the use of multipurpose tree species, (iv) wildlife conservation and use, (v) tenure, and (vi) product certification. Our conclusions remain preliminary due to the relative paucity of published studies and lessons learned on what has worked and what has not in the context of integrated management for timber and NTFPs. We propose at least three ways where further research is merited. One, in improving ‘opportunistic’ situations driven by selective timber harvesting that also enhance NTFP values. Two, to explicitly enhance both timber and NTFP values through targeted management interventions. Three, to explicitly assess biophysical, social, regulatory and institutional aspects so that combined benefits are maximized. Interventions for enhancing the compatibility of timber and NTFP extraction must be scaled in relation to the size of the area being managed, applied timber harvesting intensities, and the dynamics of multi-actor, forest partnerships (e.g., between the private sector and local communities). In addition, training and education issues may have to be re-crafted with multiple-use management approaches inserted into tropical forestry curricula.     

巴西森林资源监测及遥感技术应用的基本做法和启示

介绍了巴西森林资源基本情况,以及森林资源监测与遥感技术应用的主要做法。在此基础上总结出对我国相应工作的启示,即要研究我国森林资源监测体系的改进方案,要加大遥感技术的应用力度,要重视监测结果的社会公开。     

Rehabilitating Abandoned Pastures in Panama: Control of the Invasive Exotic Grass,Saccharum spontaneum L., Using Artificial Shade Treatments

ABSTRACT

The exotic grass, Saccharum spontaneum L., has invaded abandoned agricultural lands in the Panama Canal Watershed for decades. The grass aggressively competes with regenerating tree seedlings preventing natural forest regeneration. To estimate effectual light level for controlling the grass, the growth of S. spontaneum was measured under a range of artificial shading conditions. Five shade treatment subplots–light intensities of 100% (full sunlight), 50, 25, 15, and 5%–were established at each of eight plots in land adjacent to the Panama Canal Watershed. Each site was cleared of S. spontaneum and then the regrowth was harvested. The regrowth of the grass was harvested and measured four times every one and half months for six months. The biomass of S. spontaneum was significantly less in lower light conditions than in full sunlight. The results showed that comparing growth of the grass at each harvest date, except for the first harvest date, there were significant differences between full sunlight and light intensities of 5, 15 and 25%. When compared by different harvest dates for each light level, only full sunlight showed a significant difference in biomass of the grass. The study demonstrates that shading is an effective method for controlling S. spontaneum. The results can be applied to developing reforestation strategies for abandoned lands occupied by S. spontaneum.     

Estimates of forest biomass in the Brazilian Amazon: New allometric equations and adjustments to biomass from wood-volume inventories

Uncertainties in biomass estimates in Amazonian forests result in a broad range of possible magnitude for the emissions of carbon from deforestation and other land-use changes. This paper presents biomass equations developed from trees directly weighed in open forest on fertile soils in the southern Amazon (SA) and allometric equations for bole-volume estimates of trees in both dense and open forests. The equations were used to improve the commonly used biomass models based on large-scale wood-volume inventories carried out in Amazonian forest. The biomass estimates from the SA allometric equation indicate that equations developed in forests on infertile soils in central Amazonia (CA) result in overestimates if applied to trees in the open forests of SA. All aboveground components of 267 trees in open forests of SA were cut and weighed, and the proportion of the biomass stored in the crowns of trees in open forest was found to be higher than in dense forest. In the case of inventoried wood volume, corrections were applied for indentations and hollow trunks and it was determined that no adjustment is needed for the form factor used in the RadamBrasil volume formula. New values are suggested for use in models to convert wood volume to biomass estimates. A biomass map for Brazilian Amazonia was produced from 2702 plots inventoried by the RadamBrasil Project incorporating all corrections for wood density and wood volume and in factors used to add the bole volume of small trees and the crown biomass. Considering all adjustments, the biomass map indicates total biomass of 123.1 Gt (1 Gt = 1 billion tons) dry weight (aboveground + belowground) for originally forested areas in 1976 in the Brazilian Legal Amazon as a whole (102.3 Gt for aboveground only) at the time of the RadamBrasil inventories, which were carried out before intensive deforestation had occurred in the region. Excluded from this estimate are 529,000 km² of forest lacking sufficient RadamBrasil inventory data. After forest losses of 676,000 km² by 2006 – not counting 175,000 km² of this deforested area lacking RadamBrasil data – the estimated dry biomass stock was reduced to 105.4 and 87.6 Gt (aboveground + belowground and only above-ground). Thus, in 2006 the carbon storage in forested areas in Brazilian Amazonia as a whole will be around 51.1 Gt (assuming 1 Mg dry biomass = 0.485 Mg C). Biomass estimates by forest type (aggregated into 12 vegetation classes) are provided for each state in the Brazilian Legal Amazon.     

巴西林业资源、林产品贸易特点及对我国的启示

从林业地位、森林资源和林产品贸易三个方面介绍了巴西林业的概况,并在分析巴西林产品贸易特点的基础上,总结出对我国林产品贸易的4点启示,即要拓宽国内外市场,保证供需;稳扎稳打步步为营,形成优势出口产品品牌;内外兼顾,完善本国对外贸易法规;防微杜渐,提高管理和科技水平。巴西是世界生物资源和森林资源最为丰富的国家之一,总结和借鉴巴西林产品贸易情况对推动和促进我国林产品贸易及林业产业发展具有重要意义。     

Sustainability of tropical dry forests: Two case studies in southeastern and central Brazil

In this study, we review the current available information on the social–ecological context of Brazilian tropical dry forests (TDFs), a vegetation type that covers approximately 3% of the country territory. For this purpose, we conducted a comparative analysis of two case studies, one study in the north of Minas Gerais state and the other in Paranã River Basin, situated in southeastern and central Brazil, respectively. We compiled published bibliographical and census-based data for the two regions, concerning the historical human occupation and land use and the environmental and development policies affecting TDF management and sustainable use. Brazilian TDFs usually occur in semi-arid climates, and have been intensely converted mainly to extensive pasturelands in large farms, thus leading to high income concentration in those areas. Our case studies involve less-developed regions that support populations with very low human development indices, which is the norm for Brazilian TDFs. Many of these are traditional populations, such as indigenous and slave descendents, with peculiar cultural practices only recently considered in government policies proposed for the forest management. Though the two regions have similar land use histories, current social–ecological scenarios are very different. In the north of Minas Gerais, TDF conversion policies were debated intensely for the last 15 years, recently resulting in a state law specifically generated to regulate TDF use. Also, this region has 20 conservation units (CUs), some of them delimited inside the territories of the several traditional populations that inhabit TDF areas. This process caused enduring conflicts that can affect both CUs’ effectiveness and the sustenance of these populations. In the Paranã River Basin, there is no specific policy towards TDFs, whose use is regulated by the 43-year-old Brazilian Federal Forest Code. There are only four CUs in this region, and most traditional populations were expelled from their original territories and consequently lost their cultural identity. Government sustainability strategies are limited to the establishment of CUs, a response that may disregard social demands and cultural practices, depending on the local context. Given the uniqueness and threat level to TDFs, specific and more diversified policies towards land use should be established for these ecosystems in order to stimulate low-impact activities that maintain ecosystem services and improve the livelihoods of TDF inhabitants.     

Protection vs. commercial management: Spatial and temporal analysis of land cover changes in the tropical forests of Central India

Tropical forests worldwide are undergoing rapid changes due to increasing human populations and varied land use practices. In an effort to protect these forests and their species, the number of protected areas has increased exponentially in recent decades. Clearly protected areas play a crucial role in conservation efforts and this strategy has been found to be successful in several studies. However, protected areas are often embedded within a matrix of other land cover types, including non-protected forests, agricultural fields, or urban areas. It is therefore critical for park management to think beyond the borders of their protected areas and work to maintain ecological integrity of the surrounding matrix and the connectivity between protected areas. This study integrates remote sensing, GIS and field observations to examine the effects of different management strategies on land cover changes. As a case study we examine a tiger reserve in Central India which is surrounded by commercially managed forests, representative of many protected areas throughout India. Findings of this study show that while protected areas play an important role in conservation, alternative approaches including favorable management policies could also be effective to extend conservation over larger areas.     

硬杂小径木材干燥技术初探

我国森林资源中小径材的蓄积量占有相当大的比重,其中以硬杂树种数量最多。小径材具有带髓心、弯曲度大、节疤多等自然生长特征及干燥易裂开等问题,给干燥技术和后续加工增添了很大难度。通过对柞木、桦木等树种小径材的实验室及工业试验,认为:硬杂小径材在干燥过程中不宜采用高温介质处理,以采用较缓和的水分蒸发强度和中、低温介质为宜,应保持锯材厚度方向较平稳的温度梯度。     

Size, species, and fire behavior predict tree and liana mortality from experimental burns in the Brazilian Amazon

Anthropogenic understory fires have affected large areas of tropical forest in recent decades, particularly during severe droughts. Yet, the mechanisms that control fire-induced mortality of tropical trees and lianas remain ambiguous due to the challenges associated with documenting mortality given variation in fire behavior and forest heterogeneity. In a seasonally dry Amazon forest, we conducted a burn experiment to quantify how increasing understory fires alter patterns of stem mortality. From 2004 to 2007, tree and liana mortality was measured in adjacent 50-ha plots that were intact (B0 - control), burned once (B1), and burned annually for 3 years (B3). After 3 years, cumulative tree and liana mortality (≥1 cm dbh) in the B1 (5.8% yr⁻¹) and B3 (7.0% yr⁻¹) plots significantly exceeded mortality in the control (3.2% yr⁻¹). However, these fire-induced mortality rates are substantially lower than those reported from more humid Amazonian forests. Small stems were highly vulnerable to fire-induced death, contrasting with drought-induced mortality (measured in other studies) that increases with tree size. For example, one low-intensity burn killed >50% of stems <10 cm within a year. Independent of stem size, species-specific mortality rates varied substantially from 0% to 17% yr⁻¹ in the control, 0% to 26% yr⁻¹ in B1, and 1% to 23% yr⁻¹ in B3, with several species displaying high variation in their vulnerability to fire-induced mortality. Protium guianense (Burseraceae) exhibited the highest fire-induced mortality rates in B1 and B3, which were 10- and 9-fold greater than the baseline rate. In contrast, Aspidosperma excelsum (Apocynaceae), appeared relatively unaffected by fire (0.3% to 1.0% mortality yr⁻¹ across plots), which may be explained by fenestration that protects the inner concave trunk portions from fire. For stems ≥10 cm, both char height (approximating fire intensity) and number of successive burns were significant predictors of fire-induced mortality, whereas only the number of consecutive annual burns was a strong predictor for stems <10 cm. Three years after the initial burn, 62 ± 26 Mg ha⁻¹ (s.e.) of live biomass, predominantly stems <30 cm, was transferred to the dead biomass pool, compared with 8 ± 3 Mg ha⁻¹ in the control. This biomass loss from fire represents ∼30% of this forest's aboveground live biomass (192 (±3) Mg ha⁻¹; >1 cm DBH). Although forest transition to savanna has been predicted based on future climate scenarios, our results indicate that wildfires from agricultural expansion pose a more immediate threat to the current carbon stocks in Amazonian forests.     

国营林场产权制度改革探讨——以山西省杨树丰产林实验局云西林场为例

本文针对国营林场产权制度存在的主要问题,借鉴国有林权制度改革的经验,提出国营林场产权制度改革的初步设想。     

Tree height in Brazil's ‘arc of deforestation’: Shorter trees in south and southwest Amazonia imply lower biomass

This paper estimates the difference in stand biomass due to shorter and lighter trees in southwest (SW) and southern Amazonia (SA) compared to trees in dense forests in central Amazonia (CA). Forest biomass values used to estimate carbon emissions from deforestation throughout, Brazilian Amazonia will be affected by any differences between CA forests and those in the “arc of deforestation” where clearing activity is concentrated along the southern edge of the Amazon forest. At 12 sites (in the Brazilian states of Amazonas, Acre, Mato Grosso and Pará) 763 trees were felled and measurements were made of total height and of stem diameter. In CA dense forest, trees are taller at any given diameter than those in SW bamboo-dominated open, SW bamboo-free dense forest and SA open forests. Compared to CA, the three forest types in the arc of deforestation occur on more fertile soils, experience a longer dry season and/or are disturbed by climbing bamboos that cause frequent crown damage. Observed relationships between diameter and height were consistent with the argument that allometric scaling exponents vary in forests on different substrates or with different levels of natural disturbance. Using biomass equations based only on diameter, the reductions in stand biomass due to shorter tree height alone were 11.0, 6.2 and 3.6%, respectively, in the three forest types in the arc of deforestation. A prior study had shown these forest types to have less dense wood than CA dense forest. When tree height and wood density effects were considered jointly, total downward corrections to estimates of stand biomass were 39, 22 and 16%, respectively. Downward corrections to biomass in these forests were 76 Mg ha⁻¹ (∼21.5 Mg ha⁻¹ from the height effect alone), 65 Mg ha⁻¹ (18.5 Mg ha⁻¹ from height), and 45 Mg. ha⁻¹ (10.3 Mg ha⁻¹ from height). Hence, biomass stock and carbon emissions are overestimated when allometric relationships from dense forest are applied to SW or SA forest types. Biomass and emissions estimates in Brazil's National Communication under the United Nations Framework Convention on Climate Change require downward corrections for both wood density and tree height.     

Burning of Amazonian forest in Ariquemes, Rondônia, Brazil: biomass, charcoal formation and burning efficiency

Biomass burning in tropical forests – the normal practice to prepare land for agriculture and ranching – has been a major source of CO₂ emitted to the atmosphere. Mass transformations by burning are still little studied in the tropics. The present study estimated parameters, such as the stock of carbon contained in the biomass, burning efficiency and the formation of charcoal and ashes in a tropical moist forest. Two sets of plots arranged in the form of ‘stars' (720 m² total) were installed in a 3.5 ha area of forest that had been felled for planting pasture at Fazenda Nova Vida, Ariquemes, Rondônia. Each ‘star' had six rays measuring 2 m × 30 m; alternating rays were designated for pre-burn and post-burn measurements. All above-ground biomass present in the plots was weighed directly before the burn in the pre-burn rays and after the burn in the post-burn rays. Pieces of wood with diameter ≥10 cm also had their biomasses estimated from volume estimates, using line-intersect sampling (LIS) in order to increase the area of sampling and to allow volume loss to be estimated as an increment based on individual pieces measured before, and after, the burn at the same point (as opposed to inferring change as a difference between independent estimates of stocks). The initial above-ground biomass (dry weight) before the burn was estimated at 306.5 ± 48.6 (mean ± SE) Mg ha⁻¹, with an additional 4.5 Mg ha⁻¹ for trees left standing. Carbon stock in the initial biomass (including trees left standing) was 141.3 (Mg C) ha⁻¹. After burning, carbon stock was reduced by 36.8% (burning efficiency). The stocks of charcoal and ash formed in the burn were, respectively, 6.4 ± 2.7 and 5.7 ± 1.0 Mg ha⁻¹. The destructive and nondestructive (LIS) methods did not differ significantly (t-test, p > 0.05) in estimating post-burn stocks of wood and charcoal. The results of this study contribute to improving the estimates of parameters needed for global carbon calculations and point to ways in which estimates of these parameters could be further improved.     

Agroforestry adoption in Haiti: the importance of household and farm characteristics

Most agroforestry-adoption studies are based on surveys of "non-adopters." An understanding of the circumstances that have led to a change of attitude of the adopters will be valuable in our efforts to enhance adoption rates. This study was undertaken to provide such knowledge based on a large agroforestry extension project involving 200,000 farm families and covering 25% of all rural households in Haiti. A questionnaire-based survey of the project participants was conducted covering 1,540 households and 2,295 fields in four regions of Haiti. Information was recorded about each farm and family member through interviews with farmers and visits to their farms. The results confirmed that farmers make decisions about tree culture based on household- and field characteristics. Different farmers consider trees differently depending upon how they fit into their farm-family strategy. In general, farmers installed tree hedgerows on fields of less secure tenure, of lesser fertility, and steeper slope, while on closer, more fertile fields of greater tenure security, tree seedlings and fruit trees were more common and there was a greater density of mature trees (>10 cm DBH). More money was realized from sale of tree products on actively cropped fields in more secure tenure and having more fertile soil. Older farmers managed a greater density of trees, especially when the land was in secure tenure status. This broad-based study shows that agroforestry implementation strategies in poor countries such as Haiti should be based on a thorough knowledge of how farmers use household and field characteristics to make adoption decisions. It also suggests that agroforestry-adoption studies should account for the dynamic changes occurring during extended time periods.This revised version was published online in November 2005 with corrections to the Cover Date.