Treesearch

Recent and projected changes in climate over this century pose an unprecedented threat to the health, diversity, and productivity of forest ecosystems. Forests have migrated and adapted to long-term changes in climate over thousands to millions of years; however, natural migration rates and adaptive responses of tree populations cannot match the rapid pace of current climate change. Consequently, more climate-informed approaches to reforestation are needed as current reforestation strategies using local seed sources may no longer be adequate to meet forest management objectives. Assisted...

Globalization has spread thousands of invasive insect species into new world regions, causing severe losses in ecosystem services. Previous work proposed that plant invasions facilitate insect invasions through the creation of niches for non-native herbivores. Despite the impact of insect invasions, a comprehensive understanding is lacking on how invasion success varies among insect feeding groups. We therefore compiled the predominant larval trophic groups (herbivores, predators, parasites, detritivores, and brood-carers) for 5,839 non-native insect species in nine world regions to...

Oak decline is a major concern in Iran. A literature search with the terms ‘Iran’ AND ‘oak’ OR ‘Quercus’ from 1963 through 2023 resulted in 635 articles with over 200 dealing specifically with oak decline. In Iran, oak decline is most severe in the Zagros forests, followed by the Arasbaran and Hyrcanian forests. Of Iran's 11 native oak species, Quercus brantii is the most affected. Several factors have been identified as contributing to oak decline in Iran. Some economic and social factors include high rural unemployment, livestock overgrazing and uncontrolled cutting of live tree branches...

During the last two decades there has been growing recognition of the importance of Allee effects in population dynamics and applied ecology. The Allee effect, that is decreased fitness at lower population densities, has been recognized as potentially playing an important role in the conservation of endangered species, in the practice of biological control, and the eradication of invasive species. Although a number of theoretical studies have been devoted to the role of Allee effects in the population dynamics of insects and other terrestrial arthropods, experimental evidence documenting...

The American elm (Ulmus americana L.), once a dominant species in North American floodplain forests, has suffered significant population declines due to Dutch elm disease (DED). Despite this, some elms persist, potentially exhibiting disease resistance and climate-adaptive traits that could facilitate restoration. Understanding these traits is crucial for selecting genotypes suited to current and future climatic conditions, particularly in colder regions. This study evaluated the mid-winter cold tolerance of American elm genotypes across a climatic gradient to ascertain evidence of local...

Few studies have explored variability of associations between greenspace and cardiovascular (CVD) mortality according to demographic or neighborhood contextual factors. We estimated overall and sex-stratified associations between greenspace and CVD mortality rates in Philadelphia, PA, and quantified effect modification of the sex-stratified associations by neighborhood violent crime rates. Sex- and age-stratified census tract CVD mortality rates (years 2008–2015) were linked with proportion tree canopy cover, grass/shrub cover, and total vegetation cover, and proportion of adult residents...

Biodiversity is declining in many regions of the world. Scientists know more about the diversity of aboveground organisms (like trees, plants, and animals) because they are easier to detect and measure than belowground organisms (like bacteria and fungi). Estimating belowground biodiversity usually involves extracting and sequencing DNA from soil, an expensive process that provides information about a small area of land. Forest restoration efforts would benefit from techniques that provide belowground biodiversity data for large areas of land. In a recent study, researchers explored...

Invasions by nonnative insect species can massively disrupt ecological processes, often leading to serious economic impacts. Previous work has identified propagule pressure as important driver of the trend of increasing numbers of insect invasions worldwide. In the present article, we propose an alternative hypothesis—that insect invasions are being driven by the proliferation of nonnative plants, which create niches for insect specialists and facilitate their establishment outside their native ranges where their hosts are planted or are invasive. We synthesize mechanisms by which plant...

Changes in forest structure and shifts in tree species composition have occurred globally due to climate change and altered disturbance regimes. With climate trending toward warmer and drier conditions, these altered forest communities may reorganize in diverse and unpredictable ways. This is especially true in mountain environments where a range of vegetation types and abiotic conditions coexist. In this study, we used long-term permanent plot data from a site spanning broad environmental gradients to assess regeneration and mortality patterns in populations of aspen (Populus tremuloides)....

Forest certification programs are voluntary initiatives emphasizing sustainable forestry and harvest practices. Compliance with certification standards is enforced through third-party audits. One requirement of most forest certification systems is the use of best management practices during harvesting activities. These practices are designed to mitigate potential negative outcomes of forest management and timber harvesting activities. Best management practice implementation has been found to have a variety of positive outcomes on water quality and other resources. However, information...