Trees, Forests and People最新文献

The study examines the spatiotemporal dynamics of landscape anthropization in the Kiziba-Baluba Hunting Domain (KBHD), near Lubumbashi in southeastern Democratic Republic of Congo, facing increasing human threats. It assesses these dynamics from 1989 to 2023 using remote sensing, Geographic Information Systems (GIS), and landscape ecology principles. The results reveal a significant decrease in forest cover, declining from 70.33 % in 1989 to 26.22 % in 2023, with an annual deforestation rate of -1.84 %. This deforestation has led to the expansion of savannas (63.93 %), agriculture (5.76 %), and built-up and bare soil (0.93 %) through patch creation and aggregation. The level of landscape disturbance has increased sixfold over 34 years, from 0.42 in 1989 to 2.81 in 2023. The reduction in the size of the largest forest patch and increased spatial isolation show rising fragmentation and dissection, often followed by the attrition of residual patches. These findings highlight the inefficiency of current conservation measures in KBHD, indicating a need for restructuring management, redefining protected area boundaries, developing a suitable management plan, implementing reforestation programs, strengthening enforcement of environmental laws, and actively involving local communities.

Elevation gradients significantly influence net primary productivity (NPP), but the relationship between elevation, climate variables, and vegetation productivity remains underexplored, particularly in diverse ecological zones. This study quantifies the impact of elevation and climatic variables on NPP in northern Pakistan, hypothesizing that elevation modulates NPP through its influence on temperature and precipitation patterns. Using remote sensing data (MODIS ERA5) and advanced ecological models like the Eddy Covariance-Light Use Efficiency (EC-LUE) model and the Thornthwaite Memorial Model (TMM), we analyzed Gross Primary Productivity (GPP) dynamics across various vegetation types and elevations from 2001 to 2023. Our findings show a mean annual NPP of 323.46 g C m-2 a-1, with an annual increase of 5.73 g C m-2 a-1. Significant elevation-dependent variations were observed, especially in mid-elevation zones (401 to 1600 meters), where NPP increased at a rate of 0.174 g C m-2 a-1 per meter (R² = 0.808, p < 0.01). In contrast, higher elevations (2800-5200 meters) exhibited a decline in NPP, decreasing by -0.171 g C m-2 a-1 per meter (R² = 0.905, p < 0.001). Temperature and precipitation were key drivers, with precipitation positively correlating with NPP across all vegetation types, particularly in Evergreen Needleleaf and Broadleaf Trees. The EC-LUE model's GPP estimates closely matched MODIS data (R² = 0.82), demonstrating the model's reliability. These findings highlight the critical role of elevation and climatic factors in vegetation productivity and underscore the need for targeted ecological management and conservation strategies. The insights from this research are vital for global climate adaptation policies and sustainable development goals, contributing to ecological resilience and carbon sequestration efforts worldwide.

In western North America, fire regimes are shifting towards more frequent, larger, and more severe wildfire. There is concern that this will shift the vegetation type in many areas, especially on the lower, drier slopes. In northern California, mature serotinous conifers and resprouting shrub species easily regenerate in severe patches of any size. There is no consensus, however, regarding the effects of shrub competition on conifer recruitment; conifer response to shade varies with shade tolerance and abiotic factors. Many conifers and almost all chaparral shrubs are shade intolerant, and we expect shading to be the main driver of the inter-species competition between these taxa on dry low-elevation, slopes We chose to examine early post-fire regeneration of knobcone pine (Pinus attenuata), a shade intolerant serotinous conifer, because (a) as a serotinous species we could be assured of a high initial density of recruits, and (b) it is mainly found on lower-elevation slopes in a matrix of chaparral. We examined the competitive interactions of the pine and shrubs within the 2018 Carr and Delta fires at the third and fourth post-fire years, as well as at the 2008 Motion Fire at the 14th post-fire year, focusing on two measurements of shrub shading: inter-shrub porosity (% shrub cover) and intra-shrub porosity (species-specific ground-level light availability). Our response variables included recruitment success (recruits per ovulate cone) and growth (height). We only chose stands where knobcone pine was a minor pre-fire component to ensure a high density of vigorously resprouting shrubs. We found (1) there were significantly fewer pine recruits under shrubs, with the bulk of the shrub-induced mortality of knobcone pine occurring before the third growing season; (2) knobcone pine averaged about six established recruits per burned parent tree by the third year following fire; and (3), extrapolating from height reconstruction of post-fire knobcone pine regeneration from the 2008 Motion Fire, the remaining tree recruits are expected to persist and dominate the stand within a decade of the fire. We conclude that competition with shrubs on low elevation sites in northern California does have a negative effect on knobcone pine density but is insufficient to seriously impede a dramatic post-fire increase in conifer density when conifer regeneration arrives promptly following fire.

Bamboo has emerged as a promising option for climate change mitigation due to its rapid growth, versatility, and renewability. However, in Nepal, there exists a substantial knowledge gap on carbon (C) stock and the influence of aspect and elevation on C stock of bamboo species, particularly in areas outside forests where bamboo is dominant. Therefore, this research was conducted to quantify C stock and aspect-elevation influence on the C stock of Bambusa nutans subsp. cupulata outside the forest area. For this study, three elevation zones (0–400 m, 400–800 m, 800–1200 m) and two aspects (East and West) were considered. A total of 30 square plots having a 100 m² area were established utilizing purposive sampling due to the scattered distribution of bamboo. Non-destructive methods were applied to measure bamboo culm diameters, while composite soil samples were systematically collected from 30 cm depth using soil augers and core samplers. Clump density (400 ha⁻¹), culm density (42,480 ha⁻¹) and culm diameter (6.82 ± 0.41 cm) were highest at middle elevations (p < 0.05), with no significant difference due to aspect (p > 0.05). The total mean C stock potential of B. nutans was 148.73 ± 3.43 Mg ha⁻¹. Our results indicated a significant difference in C stock among elevation zones, with middle elevation zones (161.77 ± 6.74 Mg ha^-1) exhibiting notably higher C stock compared to both lower (150.26 ± 2.69 Mg ha^-1) and higher (134.17 ± 4.26 Mg ha^-1) elevation zones. Furthermore, East aspect was found to have significantly (p < 0.05) higher soil organic C stock (18.52 ± 1.32 Mg ha^-1) compared to West aspect (11.4 ± 1.01 Mg ha^-1). Further research is needed to explore other complex environmental interactions with C stock potential for better climate change strategies. Incorporating bamboo C into Nepal's REDD+ initiative can be crucial for optimizing opportunities to earn C credits.

Agroforestry is an emerging livelihood strategy for meeting the fundamental requirements of millions of rural households, yet quantifying its expansion and management practices in Ethiopia remains limited. This study investigated the trends, extents and drivers of agroforestry expansion and related management practices in the central highlands of Ethiopia. A two-stage sampling method was employed to select 160 rural households that engaged in home garden and woodlot agroforestry practices. The data were collected via semi-structured questionnaires, key informant interviews, and focus group discussions and analyzed using descriptive statistics, content analysis, the Kruskal-Wallis test, and the Mann‒Whitney U test. The results demonstrated that there was a significant difference in the mean size (in hectares) of home gardens and woodlot agroforestry practices (p < 0.05). There has been an increasing trend in the adoption and expansion of agroforestry practices, both in home gardens and woodlots. The rate of agroforestry expansion increased from 0.23 % before the 1980s to 3.95 % between 2011 and 2022. The expansion of agroforestry practices, particularly the increase in home garden size and woodlot establishment, was positively influenced by increased market demand, increased seedling availability, increased availability of labor, improved knowledge of agroforestry benefits, and increased proximity to homes and roads. Furthermore, the findings demonstrated that rural households implemented weeding, pruning, thinning, looping, pollarding, fertilizer application, watering, coppicing, fencing, and mulching to maintain and optimize the productivity of their agroforestry systems. Policymakers and stakeholders should consider developing targeted programs and incentives to further encourage the expansion of both home gardens and woodlot agroforestry practices.

Ochroma pyramidale (Cav. Ex Lam.) is a rapidly growing pioneer tree native to the Americas. This species is important for rehabilitating degraded areas as well as commercially due to the wood`s low density and high resistance, making it useful for producing structural cores and lightweight plywood, as well as in the wind energy industry. For at least 50 years, two varieties of this species have been recognized by botanists as well as the Lacandon people of Chiapas, Mexico. This study provides comparative data regarding three years of growth of the white and red varieties of Ochroma pyramidale, indicating ideal soil and climatic conditions for commercial plantations. The white variety had a greater rate of growth and thrives with a high average annual precipitation (2330–3236 mm) and Luvisol or Leptosol with a neutral pH and a high P content. The red variety appears to be the most widely used in other regions of the world, while the white variety is rarely used commercially.

Different shade tree species are used in various coffee production systems across the world. Outside the benefits of biodiversity protection, temperature protection, and carbon sequestration shade trees can influence soil nutrient states through litter inputs and nitrogen fixation. However, little information is available in coffee plantations whether shade tree species and type of coffee variety planted under shade tree have an influence on soil physical properties and nutrient status in coffee-based farming systems of southwestern Ethiopia. Hence, the study was carried out to investigate the effect of shade tree species and coffee varieties in coffee plantation on the physicochemical properties of the soil. The study was conducted in Chora Botor district (Chalalaki coffee plantation), located in Jimma Zone, Oromia regional states of Ethiopia. The study was superimposed on coffee farm that has been established using four released coffee varieties (7440,744, F59 and 75227) under three recommended coffee shade trees (Albizia gummifera, Millettia feruginea and Acacia abyssinica). Soil physical properties and nutrient status were investigated in response to shade tree species, coffee varieties and their combination. The results indicated that the physical and chemical properties of the soil vary across the shade trees and coffee variety grown. The effect of shade tree species on soil depends on the type of coffee varieties grown under the shade tree species, Albizia gummifera and Acacia abyssinica trees enhanced more soil nutrient content and water-holding capacity of the soil than Millttia ferrugnia. Total nitrogen, organic matter, available phosphorous, exchangeable potassium, Cations Exchange Capacity, and bulk density were higher underneath Albizia gummifera than other coffee shade tree species. On the other hand, moisture content, available P, exchangeable K and CEC were higher beneath Acacia abyssinica than other coffee shade tree species. Soil pH was negatively correlated with Millettia ferruginia. Use of Acacia abysinica and Albizia gummifera shade tree species with compatible coffee varieties could be a viable option to augment soil fertility management practices in the coffee production systems of the southwest Ethiopia.

Forest communities have a rich heritage of gathering, producing, and using non-timber forest products (NTFPs) as food. They have maintained and transferred traditional knowledge related to NTFPs through their networks over generations. Considering the food value of NTFPs, traditional knowledge has become an important social asset, and its functions in forest communities are clearly identifiable. This study systematically analyzed the research on traditional knowledge related to NTFPs as food—to demonstrate the status and trends of research in this regard—using a systematic review method and topic modeling. We found that studies predominantly focused on medicinal plants from Asian and African countries and their effect. Through topic modeling, research keywords were classified into six topics—namely, ethnomedicinal practices, biodiversity, measurement, community and food security, traditionality, and culture. This study's findings indicate three key messages—specifically, the dominance of traditional knowledge related to NTFPs as medicinal foods, a methodological gap in traditional knowledge research, and the contribution of ecosystem services of NTFPs to community sustainability.

Fire plays a critical role in nutrient cycling and species diversity but also causes severe disturbances to ecosystems. Despite remote sensing has emerged as a valuable tool to study wildfires, a lack of information regarding post-fire dynamics still remains for certain regions. This study investigated the post-fire dynamics of four burned sites in the temperate forest of Chihuahua, northern Mexico from 2009 to 2017, based on the variability of spectral indices under varied topographic conditions of aspects and slopes. The Normalized Difference Vegetation index (NDVI), Soil Adjusted Vegetation Index (SAVI), Normalized Burn Ratio (NBR), and Normalized Difference Water index (NDWI) were utilized to assess vegetation recovery on the burned sites. One-way ANOVAs and Tukey´s tests were performed to evaluate separately the effects of aspect and slope on the indices’ variability (p < 0.05). In general, the NDVI measured the highest values of the burned sites along the evaluated lapse while the NDWI indicated the lowest measures. Results indicated significant effects of aspect on NDVI and SAVI (p < 0.05), while slope significantly influenced the four evaluated indices (p < 0.05).That in turn showed northern aspects and steeper slopes to have the highest post-fire vegetation recoveries. Furthermore, aspect only affected the bi-annual variability of SAVI (p < 0.05). However, the NBR and NDWI showed higher magnitudes of change among periods than the SAVI (i. e., recovery and non-recovery). Besides registering a continuous recovery of the burned sites from the wildfire events to 2015, this study revealed the NDVI and SAVI as the most useful spectral indices for assessing post-fire vegetation dynamics in the region. Besides aspect and slope, future studies could focus on the inclusion of additional indicators to more effectively assess post-fire ecosystem dynamics in northern Mexico.

Plantation forestry is pivotal in meeting global timber and fiber demands while promoting sustainable practices. Eucalyptus plantations, renowned for their rapid growth and adaptability, have significantly expanded in tropical regions such as Thailand. Improved Eucalyptus clones have enhanced productivity, emphasizing the role of genetic improvement programs. Accurate biomass estimation in these plantations is crucial for sustainable management and bioenergy production. This study employs a nonlinear mixed model approach to evaluate tree variables combined with rotation, clones, and region on aboveground biomass (AGB) estimation. The results showed that the "rotation, clones, region" model emerged as the most precise, achieving the highest R² and the lowest SEE, ASE, and MPSE values. However, over-parameterization is a concern. The more straightforward "clone" model performed well, achieving a high R² and relatively low prediction error, with no systematic bias and comparable ASE, MPE, and MPSE values, making it a strong choice when fewer predictor variables are preferred. Our results revealed that clones H4 and K7 for the northeastern region and K58 for the eastern region show the highest annual productivity, with growth rates up to 20 t ha⁻¹ year⁻¹. The rapid AGB increment in clones K58, K62, and K7 during the first rotation suggests improved performance in subsequent rotations. As in eastern Thailand, selecting less arid sites can enhance these clones' AGB productivity. Additionally, intensive silvicultural practices could further boost their productive efficiency.