Bulbophyllum karbianglongensis (Orchidaceae, Epidendroideae), a new species from Assam, India

A new epiphytic Bulbophyllum belonging to section Cirrhopetaloides is described from tropical mixed evergreen forests of Karbi Anglong (Assam, India) with coloured photographs and line drawings. It is allied to the Bulbophyllum bicolor, B. venulosum and B. blaoense, but differs in the size and shape of pseudobulbs, the shape of the leaf blade, and flower size. A detailed description with corresponding color photos and information on the habitat is provided.

Bayesian inference of biomass growth characteristics for sugi (C. japonica) and hinoki (C. obtusa) forests in self-thinned and managed stands

Background Forests are an important sink for atmospheric carbon and could release that carbon upon deforestation and degradation. Knowing stand biomass dynamic of evergreen forests has become necessary to improve current biomass production models. The different growth processes of managed forests compared to self-managed forests imply an adaptation of biomass prediction models. Methods In this paper we model through three models the biomass growth of two tree species (Japanese cedar, Japanese cypress) at stand level whether they are managed or not (self-thinning). One of them is named self-thinned model which uses a specific self-thinning parameter α and adapted to self-managed forests and an other model is named thinned model adapted to managed forests. The latter is compared to a Mitscherlich model. The self-thinned model takes into account the light competition between trees relying on easily observable parameters (e.g. stand density). A Bayesian inference was carried out to determine parameters values according to a large database collected. Results In managed forest, Bayesian inference results showed obviously a lack of identifiability of Mitscherlich model parameters and a strong evidence for the thinned model in comparison to Mitscherlich model. In self-thinning forest, the results of Bayesian inference are in accordance with the self-thinning 3/2 rule (α=1.4). Structural dependence between stand density and stand yield in self-thinned model allows to qualifying the expression of biological time as a function of physical time and better qualify growth and mortality rate. Relative mortality rate is 2.5 times more important than relative growth rate after about 40 years old. Stand density and stand yield can be expressed as function of biological time, showing that yield is independent of initial density. Conclusions This paper addressed stand biomass dynamic models of evergreen forests in order to improve biomass growth dynamic assessment at regional scale relying on easily observable parameters. These models can be used to dynamically estimate forest biomass and more generally estimate the carbon balance and could contribute to a better understanding of climate change factors.

Economic and Life Cycle Analysis of Passive and Active Monitoring of Ozone for Forest Protection

At forest sites, phytotoxic tropospheric ozone (O3) can be monitored with continuously operating, active monitors (AM) or passive, cumulative samplers (PM). For the first time, we present evidence that the sustainability of active monitoring is better than that of passive sensors, as the environmental, economic, and social costs are usually lower in the former than in the latter. By using data collected in the field, environmental, social, and economic costs were analyzed. The study considered monitoring sites at three distances from a control station in Italy (30, 400, and 750 km), two forest types (deciduous and Mediterranean evergreen), and three time windows (5, 10, and 20 years of monitoring). AM resulted in more convenience than PM, even after 5 years, in terms of O3 depletion, global warming, and photochemical O3 creation potential, suggesting that passive monitoring of ozone is not environmentally sustainable, especially for long time periods. AM led to savings ranging from a minimum of EUR 9650 in 5 years up to EUR 94,796 in 20 years in evergreen forests. The resulting social cost of PM was always higher than that of AM. The present evaluation will help in the decision process for the set-up of long-term forest monitoring sites dedicated to the protection of forests from O3.

Assessment of tree species diversity and above-ground biomass in two disturbed tropical dry evergreen forests of Coromandel coast of India

The tree diversity and carbon stock of all woody plants were investigated in two-hectare square plots (100 m x 100 m) were established in Suryanpet (SP) and Velleripet (VP) which is tropical dry evergreen forest (TDEF) sites on the Coromandel Coast of peninsular India. All trees ? 10 cm girth at breast height measured at 1.3 m from the rooting point were enumerated. A total of 35 tree species (? 10 cm gbh) belonging to 34 genera and 23 families were recorded in tropical dry evergreen forests. Tree species richness in 27 (dominant species Dimorphocalyx glabellus Thw.) and 18 (dominant species Strychnos nux-vomica L.) in SP and VP respectively. A total density of woody plants 671 and 1154 individuals in SP and VP respectively. The basal area of trees in the two study sites SP (40.70 m2 ha-1) and VP (45.46 m2 ha-1). Most abundant families are Loganiaceae, Euphorbiaceae and Rutaceae and its family index value (FIV) is 56.14, 39.12 and 21.40 respectively. The aboveground biomass (AGB) of trees totaled in site SP (405.3 Mg ha-1) and VP (721.3 Mg ha-1). The extent of tree species diversity and estimated carbon stock of the TDEF sites, which provides the baseline data on the floristic structure and diversity of this forest for better management and conservation.

Two new species of Kalcerrytus Galiano, 2000 (Araneae: Salticidae) from Tambopata River, Madre de Dios, Peru

Jumping spiders of the genus Kalcerrytus inhabit the moist tropical forests of the Neotropical region. This genus includes 18 species, only both sexes are known for half of these and of K. leucodon only the female is known; the vast majority of species are registered for Brazil and there are records from Bolivia, Ecuador and French Guiana. Males are characterized by having a robust palp and more sclerotized than in other genera of the Freyina subtribe; females are distinguished by their broad epigynum with large funnel-shaped copulation openings and oblique edges. Two new species are herein described, and they represent the first record of the genus in Peru. Kalcerrytus mapinguari sp. nov. and Kalcerrytus yacuruna sp. nov. were collected in the Tambopata River region, which is characterized by its highly biodiverse tropical lowland evergreen forests. Illustrations of both male and female genitalia are provided as well as maps recording their distribution.

Litterfall seasonality and adaptive strategies of tropical and subtropical evergreen forests in China

Aims Tropical and subtropical evergreen broad-leaved forests (EBF) and needle-leaved forests (ENF) in China exhibit complex leaf shedding strategies in responses to soil water availability, vapor pressure deficits (VPD) and sunlight availability. However, the seasonal variations and triggers of litterfall differ significantly in tropical/subtropical forests, and there are still many uncertainties. Herein, we aim to explore the distinct climatic factors of seasonal litterfall in a climate-phenology correlation framework. Methods We collected seasonal litterfall data from 85 sites across tropical/subtropical China and used linear correlation coefficients between sunlight and rainfall to partition synchronous/asynchronous climates. Additional phase analysis and structural equation model analysis were conducted to model the climatic triggers of tropical phenology. Important Findings Results indicated two types of tropical litterfall phenology under two types of climates. In synchronous climates, where seasonal sunlight and rainfall are positively correlated, the litterfall peak of the unimodal phenology and the first litterfall peak of the bimodal phenology both happen at the end of dry season. The second litterfall peak of the bimodal phenology occurs at the end of rainy season due to water stress. In asynchronous climates, where seasonal sunlight and rainfall are negatively correlated, VPD shows consistent seasonal variations with incoming sunlight. The leaf senescence is accelerated at the end of dry season by higher VPD; while soil water deficit is in anti-phase with sunlight and mainly controls the second litterfall peak of the bimodal phenology in EBF. Our findings provide an important reference for modeling tropical phenology in Earth system models.

Fire-induced loss of the world’s most biodiverse forests in Latin America

Fire plays a dominant role in deforestation, particularly in the tropics, but the relative extent of transformations and influence of fire frequency on eventual forest loss remain unclear. Here, we analyze the frequency of fire and its influence on postfire forest trajectories between 2001 and 2018. We account for ~1.1% of Latin American forests burnt in 2002–2003 (8,465,850 ha). Although 40.1% of forests (3,393,250 ha) burned only once, by 2018, ~48% of the evergreen forests converted to other, primarily grass-dominated uses. While greater fire frequency yielded more transformation, our results reveal the staggering impact of even a single fire. Increasing fire frequency imposes greater risks of irreversible forest loss, transforming forests into ecosystems increasingly vulnerable to degradation. Reversing this trend is indispensable to both mitigate and adapt to climate change globally. As climate change transforms fire regimes across the region, key actions are needed to conserve Latin American forests.

Fragmentation disrupts the seasonality of Amazonian evergreen forests

Predictions of the magnitude and timing of leaf phenology in Amazonian forests remain highly controversial, which limits our understanding of future ecosystem function with a changing environment. Here, we use biweekly terrestrial LiDAR surveys spanning wet and dry seasons in Central Amazonia to show that plant phenology of old-growth forests varies strongly across strata but that this seasonality is sensitive to disturbances arising from forest fragmentation. In combination with continuous microclimate measurements, we found that when maximum daily temperatures reached 35 °C in the latter part of the dry season, the upper canopy of large trees in undisturbed forests shed their leaves and branches. By contrast, the understory greens-up with increased light availability driven by the upper canopy loss alongside more sunlight radiation, even during periods of drier soil and atmospheric conditions. However, persistently high temperatures on forest edges exacerbated the upper canopy losses of large trees throughout the dry season, and the understory seasonality in these light-rich environments was disrupted as a result of the altered canopy structure. These findings demonstrate the plant-climate interactions controlling the seasonality of wet Amazonian forests and show that forest fragmentation will aggravate forest loss under a hotter and drier future scenario.