Lianas Suppress Seedling Growth and Survival of 14 Tree Species in a Panamanian Tropical Forest

Lianas are a common plant growth form in tropical forests, where they compete intensely with trees, decreasing tree recruitment, growth, and survival. If the detrimental effects of lianas vary significantly with tree species identity, as is often assumed, then lianas may influence tree species diversity and community composition. Furthermore, recent studies have shown that liana abundance and biomass are increasing relative to trees in neotropical forests, which will likely magnify the detrimental effects of lianas and may ultimately alter tree species diversity, relative abundances, and community composition. Few studies, however, have tested the responses of multiple tree species to the presence of lianas in robust, well‐replicated experiments. We tested the hypotheses that lianas reduce tree seedling growth and survival, and that the effect of lianas varies with tree species identity. We used a large‐scale liana removal experiment in Central Panama in which we planted 14 replicate seedlings of 14 different tree species that varied in shade tolerance in each of 16 80 × 80 m plots (eight liana‐removal and eight unmanipulated controls; 3136 total seedlings). Over a nearly two‐yr period, we found that tree seedlings survived 75% more, grew 300% taller, and had twice the aboveground biomass in liana‐removal plots than seedlings in control plots, consistent with strong competition between lianas and tree seedlings. There were no significant differences in the response of tree species to liana competition (i.e., there was no species by treatment interaction), indicating that lianas had a similar negative effect on all 14 tree species. Furthermore, the effect of lianas did not vary with tree species shade tolerance classification, suggesting that the liana effect was not solely based on light. Based on these findings, recently observed increases in liana abundance in neotropical forests will substantially reduce tree regeneration, but will not significantly alter tropical tree species diversity, relative abundance, or community composition

Selecting Tree Species with High Carbon Stock Potency From Tropical Upland Forest of Bedugul-Bali, Indonesia

Vegetation studies to reveal tree diversity and its contribution to carbon stock were conducted in three different sites of upland forest in Bali, Indonesia. The sites were located approximately 60 km north of the Bali Province capital city of Denpasar in an area named Bedugul. Those three sites were Mt. Mangu (forest area east of Beratan lake), forest area west of Buyan lake and forest area south of Tamblingan lake. There were 44, 29, and 21 tree species of 14, 19, 14 families with Shannon Diversity Index (H) of 2.87, 2.64 and 1.69 respectively. Carbon stock average of above ground tree biomass from these sites were 214.2, 693.0 and 749.1 ton.ha-1 respectively. Tree species with top Summed Dominance Ratio (SDR) in each of those sites were Platea latifolia in Mt. Mangu, Planchonella sp. in Buyan, and Tabernaemontana macrocarpa in Tamblingan. Average carbon content of these three species were 493.25, 12,876.26 and 40.35 kg.ha-1 respectively

Selection of native trees for intercropping with coffee in the Atlantic Rainforest biome

A challenge in establishing agroforestry systems is ensuring that farmers are interested in the tree species, and are aware of how to adequately manage these species. This challenge was tackled in the Atlantic Rainforest biome (Brazil), where a participatory trial with agroforestry coffee systems was carried out, followed by a participatory systematisation of the farmers experiences. Our objective was to identify the main tree species used by farmers as well as their criteria for selecting or rejecting tree species. Furthermore, we aimed to present a specific inventory of trees of the Leguminosae family. In order to collect the data, we reviewed the bibliography of the participatory trial, visited and interviewed the farmers and organised workshops with them. The main farmers' criteria for selecting tree species were compatibility with coffee, amount of biomass, production and the labour needed for tree management. The farmers listed 85 tree species; we recorded 28 tree species of the Leguminosae family. Most trees were either native to the biome or exotic fruit trees. In order to design and manage complex agroforestry systems, family farmers need sufficient knowledge and autonomy, which can be reinforced when a participatory methodology is used for developing on-farm agroforestry systems. In the case presented, the farmers learned how to manage, reclaim and conserve their land. The diversification of production, especially with fruit, contributes to food security and to a low cost/benefit ratio of agroforestry systems. The investigated agroforestry systems showed potential to restore the degraded landscape of the Atlantic Rainforest biome

Tree-mediated methane emissions from tropical and temperate peatlands

Methane production and transport processes in peatlands are fairly well understood, but growing evidence for emission of methane through trees has highlighted the need to revisit methane transport processes. In wetland trees, morphological adaptations such as development of hypertrophied lenticels, aerenchyma and adventitious roots in response to soil anoxia mediates gas transport, transporting both oxygen from the atmosphere to oxygen-deprived roots and soil-produced methane from the root-zone to the atmosphere. Although, tree-mediated methane emissions from temperate tree species have been confirmed, methane emissions from tropical tree species and processes that control tree-mediated methane emissions remain unclear. This study explains the role of trees in transporting soil-produced methane to the atmosphere and uncovers the principal mechanisms of tree-mediated methane emissions. Methane emissions from eight tropical tree species and two temperate tree species were studied in situ. The mechanisms and controls on tree-mediated methane emissions were investigated using three year old common alder (Alnus glutinosa; 50 trees) grown under two artificially controlled water-table positions. Methane fluxes from whole mesocosms, the soil surface and tree stems were measured using static closed chambers. Both temperate and tropical tree species released significant quantities of methane, with tropical trees dominating ecosystem level methane fluxes. In temperate peatlands, both the methane gas transport mechanism and quantity of methane emitted from stems is tree-species dependent. In Alnus glutinosa, no correlations were observed between stomatal behaviour and tree-mediated methane emissions, however, stem methane emissions were positively correlated with both stem lenticel density and dissolved soil methane concentration. In Alnus glutinosa, no emissions were observed from leaf surfaces. The results demonstrate that exclusion of tree-mediated methane emissions from flux measurement campaigns in forested peatlands will lead to an underestimation of ecosystem-wide methane emissions

The Growth Dynamics on Tree Species of Fagaceae Family in a Tropical Montane Rain Forest of West Java, Indonesia

A one ha (100 x 100 m ) permanent plot each was established at sub-mountain (1000 m altitude) and mountain forests (1800 m altitude)in Gunung Halimun National Park,West Java in 1996.Both plots were monitored periodically in order to understand the population dynamics of tree species, an important aspect on understanding forest ecology.Number of individuals and total basal areas of Fagaceae species represented about 10 and 20.5% of total species in sub-mountain and 38 and 56.1% of total species in mountain forest.The distribution pattern of tree height(H, in m) of the similar diameter (D in cm) was consistently lower in mountain forest than of sub-mountain forest.The highest mortality index in sub-mountain and mountain forests was occurred on Lithocarpus sp.(ruui) and Castanopsis acuminatissima, respectively.As a whole, in both study sites, number of mortal individuals of all Fagaceae species during 1996-200 was higher than of recruit individuals.The growth and population dynamics of the Fagaceae species in both sites within 1996-2000 study periods were also discussed

Observations on the biology of the South African checkered beetle Aphelochroa sanguinalis (Westwood) (Coleoptera: Cleridae)

The checkered beetle Aphelochroa sanguinalis (Westwood) (Coleoptera: Cleridae) is found in savanna and woodland ecosystems of southern and eastern Africa. During surveys for insect floral visitors in the Skukuza Ranger District of Kruger National Park, South Africa, we encountered adults of Aphelochroa sanguinalis on flowers of two tree species, Acacia grandicornuta Gerstner and Acacia tortilis (Forsskal) Hayne (Fabaceae). These two tree species flower in the early rainy season (November-December) and have small white flowers in small round ball-shaped clusters. Adults of phelochroa sanguinalis were not found on flowers of 14 other tree species with different floral structures which were flowering at the same time as Acacia grandicornuta and Acacia tortilis. Predatory, reproductive, and defensive behaviors (including the presence of a chemical defense) are described for Aphelochroa sanguinalis based on field and laboratory observations

Distribution of First Instar Gypsy Moths (Lepidoptera: Lymantriidae) Among Saplings of Four Tree Species Common in the Great Lakes Region

We examined the inter-tree distribution of first instar gypsy moth larvae under natural dispersal conditions in the field in Michigan in 1991. The study focused on saplings of northern red oak (Quercus rubra), white oak (Q. alba), red maple (Acer rubrum), and witch-hazel (Hamamelis virginiana), which are common understory components of forests in the Great Lakes region. Large-volume trees with foliage that is well-developed early in the spring should provide an excellent surface area for catching newly-hatched gypsy moth larvae, which are randomly dispersed by wind in the spring around the time of leaf flush or shortly thereafter. Comparing across tree species in our study, red maples had the largest crown volumes and wellflushed leaf material, but very few larvae were found on these trees at both sampling times in mid-May. Despite the lack of larvae on red maple, these trees were liberally covered with gypsy moth silk, indicating that many larvae landed on these plants but left rapidly when they apparently found the trees to be an unacceptable food source. Among the other three tree species, patterns of larval distribution reflected levels of host phenological development during both sampling periods, with more insects occurring on tree species that had more advanced leaf development. The highest numbers of larvae were found on northern red oak and witch-hazel. Intermediate num­bers of insects were present on white oak. Trends in insect distribution also paralleled patterns seen in tree phenology across slope gradients. Defoliation ratings corresponded well to measures of first instar presence for each tree species. Northern red oak and witch-hazel trees experienced more early defoliation on average than did red maple and white oak. For those tree species that are acceptable hosts of the gypsy moth, average level of phenological development for a given tree, species, or forest stand at the time of larval dispersal can be an important predictor of plant or stand susceptibility to gypsy moth establishment and subsequent defoliation

Status, distribution and use of threatened tree species in the walnut-fruit forests of Kyrgyzstan

Information is lacking on the status of threatened tree species in Central Asia. This paper aims to provide preliminary information for 10 fruit and nut tree species of Kyrgyzstan. A field survey was conducted throughout the range of walnut-fruit forests in this country, supported by a socio-economic survey. Results indicated that species differed markedly in abundance. Whereas Malus sieversii was found in all locations, four species (Crataegus pontica,Pistacia vera,Pyrus korshinskyi and Sorbus persica) were only found in a minority (≤ 30%) of sites. Four species showed evidence of a bimodal distribution of stem diameters, which could be attributed to fuelwood harvesting, as indicated by the socio-economic survey. A majority of respondents reported a decline in the available grazing resource, a decline in the availability of harvested fruits and an increase in time required to collect fuelwood over the past decade. These results suggest that unsustainable land-use practices may be impacting negatively on populations of threatened fruit tree species. These results highlight the need to regulate local forest use to ensure that threatened fruit and nut tree species are effectively conserved, and the need for targeted actions to conserve the most threatened species, such as P. korshinskyi. © 2014 © 2014 Taylor & Francis

The role played by exotic plants in urban ecosystems: comments on Spennemann, 2019

The article written by Dirk HR Spennemann, and published in the European Journal of Ecology, addresses the role played by a palm tree species native to the Canary Islands as food source for several frugivore species found in Australian cities. This palm tree bears fruit throughout the year; therefore, it is a reliable food source in winter and helps increasing wildlife support. Spennemann avoids the native versus exotic dogmatic simplism; instead, he assesses the palm tree species based on its positive environmental impact