Living Tree Species Research Articles

Discovering the mechanisms of plant longevity to fight human aging and age related diseases

Aging is one of the most complex and challenging problems in biology. Therefore, many models from yeast to mammals are widely used to discover the mechanisms of human aging in order to postpone it and prevent age related diseases. According to the evolutionary theory of aging [1], natural selection only affected early life traits like fitness and reproduction, due to predation and accidents that prevent the becoming old of animals in the wild. But it likely failed to prevent late life phenotypes like aging and even contributed or caused them by antagonistic pleiotropy. In contrast to animals, plants, especially trees, live in a protected environment and are not subject to predation. This should have allowed natural selection to prevent late life's deleterious effects in at least some plants. The presence of very long living tree species like Pinus longaeva that lives up to 5000 years [2] and 9550 years old spruce which is the oldest living tree [3], suggest that natural selection has found a way to prevent aging. In this study, the present literature on plant longevity and senescence was scrutinized and a working frame including leaf senescence [4] and seed longevity [5] was described for further studies. The wide range health benefits of pycnogenol [6], a bark extract of pine that is also a long living tree, gives the hope to discover other phytochemicals ensuring plant longevity from especially oldest living plants that have the potential to be weapons in our war against aging and age associated diseases.

Habitat characteristics, age, and arrival date of male Red-breasted Flycatchers Ficedula parva

Avian territory quality can vary with the availability of good habitats, the structure of the population, the age and quality of individuals. Here, we describe the territories of the Red-breasted Flycatcher Ficedula parva in relation to male age and arrival time. In the territories of Red-breasted Flycatchers, hornbeam Carpinus betulus was the dominant live tree species and spruce Picea abies was the dominant snag (standing dead tree) species. Snags constituted 20.2% of tree stands. The density of live trees ranged from 164 to 680 indiv./ha (x = 410 ± 123.8), and density of snags ranged from 0 to 156 indiv./ha (x = 4.2 ± 22.5). Old males settled on territories earlier in the season than did young males. Living tree density and circumference of trees and snags differed between old and young males. Old males settled on territories with larger live trees, larger snags and higher living tree densities than did younger males. Male age, however, was not related to the density of snags nor to tree species composition, this suggested that old males probably chose territories with a greater density of living trees and old stands to reduce vulnerability to predation.

A spatially interactive simulation of climate change, harvesting, wind, and tree species migration and projected changes to forest composition and biomass in northern Wisconsin, USA

AbstractIn the coming century, forecast climate changes caused by increasing greenhouse gases may produce dramatic shifts in tree species distributions and the rates at which individual tree species sequester carbon or release carbon back to the atmosphere. The species composition and carbon storage capacity of northern Wisconsin (USA) forests are expected to change significantly as a result. Projected temperature changes are relatively large (up to a 5.8°C increase in mean annual temperature) and these forests encompass a broad ecotone that may be particularly sensitive to climate change. Our objective was to estimate the combined effects of climate change, common disturbances, and species migrations on regional forests using spatially interactive simulations. Multiple scenarios were simulated for 200 years to estimate aboveground live biomass and tree species composition. We used a spatially interactive forest landscape model (LANDIS‐II) that includes individual tree species, biomass accumulation and decomposition, windthrow, harvesting, and seed dispersal. We used data from two global circulation models, the Hadley Climate Centre (version 2) and the Canadian Climate Center (version 1) to generate transient growth and decomposition parameters for 23 species. The two climate change scenarios were compared with a control scenario of continuing current climate conditions. The results demonstrate how important spatially interactive processes will affect the aboveground live biomass and species composition of northern Wisconsin forests. Forest composition, including species richness, is strongly affected by harvesting, windthrow, and climate change, although five northern species (Abies balsamea, Betula papyrifera, Picea glauca, Pinus banksiana, P. resinosa) are lost in both climate scenarios regardless of disturbance scenario. Changes in aboveground live biomass over time are nonlinear and vary among ecoregions. Aboveground live biomass will be significantly reduced because of species dispersal and migration limitations. The expected shift towards southern oaks and hickory is delayed because of seed dispersal limitations.

Clinical Use and Molecular Mechanisms of Action of Extract of Ginkgo biloba Leaves in Cardiovascular Diseases

Ginkgo biloba is one of the oldest living tree species that has been referred to as a living fossil. Extract from Ginkgo biloba leaves (GBE) is among the most commonly used herbal drugs and is popularized for its alleged tonic effect and possible curative and restorative properties. There is an increasing evidence of the potential role of GBE in treating cardiovascular diseases. We examined the history of GBE usage and reviewed the literature on its effects on the cardiovascular system. In the extensive studies involving cell cultures and animal models, GBE has been shown to exert its action through diverse mechanisms. GBE has been reported to have antioxidatant properties, to modify vasomotor function, to reduce adhesion of blood cells to endothelium, to inhibit activation of platelets and smooth muscle cells, to affect ion channels, and to alter signal transduction. In addition, relevant clinical trials with CBE are being carried out, particularly in the treatment of arterial and venous insufficiency and in the prevention of thrombosis. Finally, the controversial clinical findings and the possible adverse interactions between GBE and other drugs are discussed. This review underscores the potential benefits of Ginkgo biloba in cardiovascular diseases, highlights the gaps in our current research, and suggests the necessity for more rigorous systematic investigation of cardiovascular properties of CBE.

Bird Communities of Early-Successional Burned and Logged Forest

Because logging has replaced fire as the most extensive and frequent disturbance regime in northeastern Minnesota, monitoring bird populations and their habitats has become increasingly important. We surveyed early-successional forests created by fire or logging for birds and their habitat during the 1994 and 1995 breeding seasons. We found that overall bird species richness and number of individuals (territorial males/ ha) were higher (P < 0.05) in burned forests than in logged forests. The American crow (Corvus brachyrhynchos), house wren (Troglodytes aedon), common yellowthroat (Geothlypis trichas), clay-colored sparrov (Spizella pallida), song sparrow (Melospiza melodia), Lincoln's sparrow (M. lincolnii), and brown-headed cowbird (Molothrus ater) were more abundant in burned areas. The Nashville warbler (Vermivora ruficapilla), chestnut-sided warbler (Dendroica pensylvanica), black-throated green warbler (D virens), and mourning warbler (Oporornis agilis) were present in greater numbers in the logged areas. We related these differences in bird presence and abundance to vegetation differences in the burned and logged habitat types. Burned areas had higher densities of dead trees, wider size ranges of dead trees, and greater heterogeneity in the shrub layer. Logged areas had higher densities of live trees, more live tree species, and wider size ranges of live trees. Red maple (Acer rubrum) was the live tree species found in greatest abundance in logged areas. If management goals include simulating natural disturbances like fire and maintaining bird populations, more dead trees should be left within logged habitats and the variability among logged areas should be increased.

Denning Habits of Common Brushtail Possums, Trichosurus Vulpecula, in New Zealand Lowland Forest.

Fifty-five T. vulpecula were radio-tracked to 182 den sites on 1987 occasions in the podocarp and mixed hardwood forest of the Orongorongo Valley, near Wellington. Most dens (92%) were above ground in trees, particularly in large trees with many clumps of perching epiphytes; the remainder were under fallen logs or trees or in dense tangles of gorse. Melicytus ramiflorus was the most commonly used living tree species. Others used commonly were Knightia excelsa, Elaeocarpus dentatus, Laurelia novaezealandiae [L. novae-zelandiae] and Podocarpus totara. Use was not dictated solely by availability. Trees without perching epiphytes were hardly ever used. Each possum used 11-15 den trees/yr, most only occasionally; the 3 most commonly used den trees accounted for 60-75% of observations. Males used more dens than females, and the sexes differed in their frequencies of the use of the various tree species, though not in the species used. Possums changed dens frequently, on average 2 nights in 3. Den sharing was uncommon, but many dens, including those on the ground, were used sequentially by several (up to 9) different possums. Dens on the ground were used mostly in autumn and winter, by possums in poor condition or after prolonged heavy rain. The implications of den site choice and use by possums are discussed, particularly in relation to den sites as a limiting resource, and the role of dens in the transmission of bovine tuberculosis. There was about a 50% chance that a den would be occupied by different possums within the probable survival period of deposited tuberculosis bacilli.

Distribution and Habitats of the Formosan Subterranean Termite (Isoptera: Rhinotermitidae) in South Carolina

The current distribution of the Formosan subterranean termite (FST), Coptotermes formosanus Shiraki, in South Carolina was determined using four survey techniques: a state-wide mail survey of pest control firms, a field sampling of trees and utility poles, a review of pest control firm treatment records for FST infested structures, and light trap collections. Based on sampling of trees and utility poles, FSTs were observed infesting utility poles and 17 live tree species. Utility poles proved to be a less sensitive indicator of FST activity than trees. Of the 18.8-km2 area currently infested in greater Charleston, an area of 11.6 km2 (directly surrounding the initial FST collection site) can probably be attributed to natural FST dispersal through swarming. The remaining isolated sites are probably due to introduction of infested material (i.e., railroad ties, plant material, etc.). The potential outcome of continuing current disposal practices for FST-infested material is discussed, along with suggestions to limit its future spread.