Trees, Forests and People最新文献

Syria has been struggling with a prolonged and brutal war for over a decade, leaving much of the country in devastation and its forests severely degraded. While many studies have identified logging for firewood as a significant driver of deforestation during the war, there is a notable absence of research specifically addressing logging behavior within the context of war. This research seeks to address this gap by examining the changes in logging behavior among local communities, the effects of violence and socioeconomic variables on wood harvesting, the contribution of wood income to people's survival during the war. To do that, we conducted survey questionnaires in two coastal villages in Syria—Blouta and Nehel al Annaze—which experienced high and low levels of violence, respectively. Our findings reveal that logging activities increased once the war began, with more people involved in forest harvesting and average days spent logging per week significantly increasing from 1.5 to 4. Additionally, the war appeared to reduce the gender disparity in logging activities: before the conflict, women engaged in logging significantly more frequently than men, but this difference became insignificant during the war. The level of violence alone did not significantly affect the amount of wood logged per month. Furthermore, income generated from wood harvesting played a substantial role in bridging the gap between the monthly income needed to cover their basic necessities and the actual income of families in both villages by 46.94 % and 84.83 % of the gap in Nehel al Annaze and Blouta, respectively. These results highlight the crucial role of forest resources in supporting rural livelihoods during times of war. Post-war effective forest management will be vital to ensure the sustainable use and recovery of forest resources, supporting both ecological restoration and economic stability for the rural communities.

Woody aboveground biomass (AGB) including short-rotation Populus is used as a feedstock for renewable and carbon-neutral bioenergy. While woody AGB can be estimated with allometric equations requiring labor-intensive field data, remote sensing technologies like mobile terrestrial light detection and ranging (LiDAR) can estimate woody AGB quickly and accurately. Therefore, the goals of this study were to develop a model to predict woody AGB of 2-year-old Populus spp. from three taxa (P. deltoides, P. deltoides × P. maximowiczii and P. deltoides × P. trichocarpa) using allometric (height and diameter at breast height (DBH)) or LiDAR-derived metrics from a mobile terrestrial (backpack) system. Likewise, we sought to compare LiDAR-estimated tree height and DBH with field-measured values. We found that a taxa-specific model containing LiDAR-measured tree height, crown volume, and taxa interactions with the height of the 10^th percentile, and the density of the lowest interval (density metric 0) explained 84 % of the variation in woody AGB with a root mean square error (RMSE) of 28.7 % and performed slightly better than the allometric model. The best model excluding taxa had a slightly higher RMSE but lower bias than the allometric model. LiDAR-derived tree heights were highly correlated with field-measured heights, but DBH could not be estimated accurately. Therefore, terrestrial mobile LiDAR systems can accurately estimate woody AGB and tree height of Populus in short rotation systems to aid in the fast and efficient quantification of woody bioenergy production and renewable energy resources.

This study develops a dynamic bioeconomic model using the Bellman equation to derive the optimal management strategy for Witches’ Broom Disease of Lime (WBDL) and the optimal replanting age of citrus trees after the first attack under multiple scenarios of disease management options and climate conditions. In addition, the study investigates different scenarios of disease presence and spread given different climatic conditions of arid, semi-arid and tropical zones in Oman. Factors such as disease incidence, severity, spread, and specific climatic conditions of three growing regions are considered. The farmers' optimal disease mitigation decision is determined by the disease density and insect vector level on the farm, and adverse climate conditions have a significant negative impact on the economic value of citrus cultivation. Results indicate that management measures by citrus growers and policymakers should be based on the climatic conditions of the growing region with a high level of treatment frequency and intensity in the arid region, and lime production should be concentrated in the tropical and semi-arid regions of the country.

M. oleifera (Moringa) is a multipurpose tree with the potential to contribute nutrients to people's diets as well as pharmacological benefits. It is widely distributed in low- and middle-income countries, yet it remains underutilized. Here, we examine the potential of M. oleifera to improve rural people's food security and dietary diversity. We focus on Malawi, where 35 % of children under the age of five suffer from stunting and 51 % of the population is classified as severely food insecure. We draw on a survey with 60 women in rural Malawi detailing food security, dietary diversity, and consumption of different M. oleifera parts and products. Using Poisson regressions, we found that M. oleifera tree ownership is associated with a 28 % decrease in food insecurity levels. Moreover, people with awareness of the benefits of M. oleifera consumption were more likely to consume leaf powder compared to people without the same awareness. Specifically, each additional benefit mentioned by women increased the odds of powder consumption by a factor of 4.6. As such, our findings highlight 1) the underutilized potential of M. oleifera in local people's food security, and 2) how awareness can be key to increased consumption. Policies should be designed to raise awareness and educate rural communities about the benefits of M. oleifera, targeting communities, schools, and healthcare facilities. Finally, M. oleifera products could provide rural women with opportunities to increase household income, contingent on establishing contracts with exporters and collectors.

The measurement of tree-rings of Cedrela fissilis was used to determine the variability of diametric and basal growth across three sites located in the Cerrado biome in Bolivia and one in the Atlantic Forest, Santa Catarina, Brazil. The growth variability in growth is particularly pronounced among sites when trees have smaller diameters and during the initial 50 years of their lives. Initial growth rates are generally higher in those sites recovered from agricultural to forest lands or highly impacted forests than those growing in well-established forests. Optimal basal growth for the four sites occurs between 60 and 80 years old. The estimated times required for C. fissilis trees to grow from a given diameter to the next one are longer at the JBA and LCH sites. Under optimal conditions, this species requires 12 years to grow from 1 to 10 cm in diameter at STA. Conversely, when growth is slower and the diametric size is larger, they need about 23 years to grow from 31 to 40 cm. The JBA and LCH sites require >100 years to reach diameters of 50 cm, the AAI (Average Annual Increase) of 0.83 cm for diameters of 1–10 cm corresponds to STA, while in this same diametric class, the lowest of 0.36 cm corresponds to LCH. In diametric sizes of 41–50 cm, the highest growth of 0.47 cm corresponds to INP and the lowest of 0.31 cm to STA. The average time necessary to grow diameters of 10 cm, the lowest is 19.2 years corresponding to the site of INP and LCH requires an average of 22.4 years.

The age of the trees required to be part of the deck, in order to achieve optimal growth, is dependent on to site-specific factors, such as light and soil nutrients. By combining this information with data on passage times, it is possible to project forest management based on an understanding of the specific events in which trees of this species change their growth dynamics within a given site or biome.

The Sub-tropical forests of Pinus roxburghii (chir pine) provide various ecosystem services and act as watershed for low lying regions. However, this species is prone to human induced fire primarily due to local communities' dependence for various resources exacerbated by the current dry conditions. The impact of fire across various vegetation layers and developmental stages has not been thoroughly studied. Bearing to this, the present study was conducted using composite burn index to assess the severity on various layers of vegetation and their long-term impact through a chronological approach. The impact of fire on 40 representative circular plots with a radius of 30 m, categorized into five forest strata: large and intermediate trees, seedlings/saplings, pole stage, shrubs, and soil were investigated and compared across four different time interval: unburnt (B0), burnt two years ago (B2), burnt five years ago (B5), and burnt 15 years ago (B15). The results were statistically proved using Kruskal–Wallis followed by Dunn's Post Hoc and Friedman test with the Holm correction in R Language. The study revealed significant variations in the average burn severity for each treatment, with shrubs having the highest average score of burn severity (average = 1.4) and soil showing the lowest (average = 0.408). The results of the Friedman test indicated non-uniform distribution of burn severity across different ecological treatments. This study is contributing significant insights into the effects of forest fires and their severity on different vegetation layers, which can be instrumental in devising and executing successful restoration strategies.

Local knowledge (LK) is often overlooked in the decision-making process during landscape restoration process. In this study, we focus on the Zicuirán-Infiernillo Biosphere Reserve as a case study. We propose a framework to incorporate LK into public policy instruments for implementing restoration interventions in Mexican protected natural areas (PNAs). Through semi-structured interviews, participant observation, and informal talks, conducted with residents from two communities located in the buffer zone and the border area of the reserve, we gathered valuable insights regarding the following: (1) the inhabitants' LK of the ecology and contributions of tropical dry forest, (2) the socioeconomic and environmental issues identified by these communities in their localities, (3) ecological and socioeconomic actions suggested by the residents to recover the forest or halt its degradation, and (4) the role of institutions and local organizations in restoration and conservation processes. Our findings indicate that residents recognized changes in species distribution and identified native trees that are tolerant to drought. Moreover, they acknowledged the beneficial contributions provided by forests, including climate and water cycle regulation, oxygen supply, and raw materials. Local people also demonstrated their awareness of environmental and socioeconomic issues and proposed activities to reverse vegetation cover loss and halt forest degradation. While reforestation emerged as the primary solution for forest recovery, assisted natural regeneration and natural regeneration were also suggested. Based on our results, we propose a framework that emphasizes a robust knowledge exchange among stakeholders, for facilitating the inclusion of LK in an ecological restoration-based education program. It is crucial for Mexican public policy instruments operating in PNAs to consider local knowledge to enhance the effectiveness of ecological restoration.

Forest fires are the main threat to ecosystems and human life. The frequency, seasonality, extent and severity of fires affect ecosystems and the physical and chemical properties of the soil by direct (heating) and indirect (ash) effects. This could affect biodiversity and forest residency in the face of climate change. In this study, we evaluated the impact of fire severity on soil physical and chemical properties caused by forest fires in a high Andean area of Peru. For this purpose, the severity levels, the degree of hydrophobicity, and the physical and chemical properties of the soil were analyzed by sampling in affected areas (Pinus radiata D. Don plantation and shrubland) and unaffected areas. The results showed a very low severity in soil components, with a strong hydrophobicity, more persistent in the forest plantation area than in the shrubland. The physical properties of the soil did not show variations; however, in the Pinus plantations they showed variations in their chemical properties such as pH, electrical conductivity, organic matter, nitrogen and cation exchange capacity compared to areas not affected by the forest fires. Likewise, in the study area an adequate regeneration process was evidenced; in fact, it is important to apply mechanisms to accelerate the restoration of the vegetation cover and the physical and chemical quality of the vegetation.

Tree ownership is typically tied to land ownership in many societies worldwide. Still, in India, tribal communities have customary ownership over trees in public forestlands, raising questions about what those trees are, where they are located, their characteristics, and whether socioeconomic factors influence their distribution and density. To address these questions, we conducted household interviews and a Global Positioning System (GPS) mapping in Sahritola, a village in the State of Jharkhand, India. We employed Kruskal Wallis, Spearman correlation, and Moran's Index to analyze the collected data. The villagers have been protecting and managing over 18,000 trees in public forestlands, including species such as asan (Terminalia tomentosa), sal (Shorea robusta), and mahua (Madhuca longifolia). Over 80 % of those trees are under individual ownership, while around 20 % are under shared ownership. Additionally, over 60 % of households owned between 100 and 500 trees. Customarily-owned tree species sharing similar characteristics (e.g., height, crown width, and diameter-at-breast-height) tend to cluster together. The number of customarily owned trees is influenced by their economic value and socioeconomic factors (e.g., religion, forestland, etc.). Additionally, the type of customary ownership (individual or shared) influences the characteristics of trees. This study could guide policymakers in potentially developing forest policies that consider the concept of customary tree ownership to promote sustainable management of forest resources in India and beyond.

Projected trends of intensified wildfires due to climate warming and fuel-load accumulation are expected to significantly alter fungal diversity, but we know little about how these changes will impact ecosystem services. We aimed to analyze how large wildfires alter the capacity of fire-prone Mediterranean ecosystems dominated by Pinus pinaster Ait. to deliver the provisioning ecosystem service of mushroom production throughout the post-fire succession. We assessed this at early (<10 years), medium (10-20 years), and late (>20 years) stages after fire, compared to an unburned forest. Our results evidenced that large wildfires significantly reduced the capacity of these forests to provide mushroom harvesting opportunities. This adverse effect was most pronounced in the first few years after wildfire but persisted even after 20 years of post-fire succession. The total fungal species richness, abundance, diversity, and productivity at the post-fire successional stages remained lower than in the unburned forest, failing to reach their pre-fire levels even after two decades. However, the presence of commercially valuable edible fungal species, along with their species richness and productivity, began to recover in the medium and late stages after fire. In the immediate aftermath of the fire, saprotrophic fungal species dominated, while mycorrhizal species became more prevalent during the medium and late stages of secondary succession. Additionally, the abundance and productivity of mycorrhizal species in the late succession stage approached those found in the unburned forest. Soil pH and biochemical variables (microbial biomass C and β-glucosidase enzymatic activity) were key drivers of changes in species composition along the successional stages. This knowledge is essential to guide management solutions aimed at reducing ecosystem service loss and increasing resilience to the new scenario of extreme large wildfire events at shorter fire-free intervals, especially in southern Europe.