19th Jan 2020
The landscapes of the future might look very different to those today, and many have argued that increasing tree cover is essential to mitigate the worst effects of climate change. But forests affect many natural processes, including water availability. We systematically reviewed the
literature to determine how forests will affect river flow over long periods of time. Annual river flow declined significantly as forests aged, but the effect was smaller in drier years, suggesting that forests were reducing water use in response to availability. Forests planted on agricultural land also had smaller effects on river flow. In contrast to
previous studies we found little evidence that the effects of forests on river flow will be reduced with age. These results highlight the importance of planning for reforestation at the landscape scale and taking local cultural and ecological contexts into account. Bentley and Coomes (2020) Global Change Biology.
10th Oct 2019
Tropical forests harbour remarkable density and diversity of woody plants, but how different processes interact to enable so many species to co-exist despite intense competition for resources is yet unresolved.
Traditionally, tropical diversity has been studied by establishing field inventory plots, but this is difficult and labour-intensive task, which limits the area that can be surveyed. In our latest paper, we use remote observation approaches to map how plant diversity changes over an entire landscape … Continue reading
Changes in leaf functional traits of rainforest canopy trees associated with an El Niño event in Borneo
7th Jul 2019
El Niño events generate periods of relatively low precipitation, low cloud cover and high temperature over the rainforests of Southeast Asia, but their impact on tree physiology remains poorly understood. Here we use remote sensing and functional trait approaches – commonly used to understand plant acclimation to environmental fluctuations – to evaluate rainforest responses to an El Niño event at a site in northern Borneo. Spaceborne measurements (i.e. NDVI calculated from MODIS data) show the rainforest canopy greened throughout 2015, coinciding with a strengthening of the El Niño event in Sabah, Malaysia, then lost greenness in early 2016, when the El Niño was at its peak. Leaf chemical and structural traits measured for mature leaves of 65 species (104 branches from 99 tree canopies), during and after this El Niño event revealed that chlorophyll and carotenoid concentrations were 35% higher in mid 2015 than in mid 2016. Foliar concentrations of the nutrients N, P, K and Mg did not vary, suggesting the mineralisation and transportation processes were unaffected by the El Niño event. … Continue reading
6th Jun 2019
The complexity of tree architecture may be the reason we find trees relaxing but it is hard to account for in ecology.
Along with our colleagues from UCL and Wageningen University, we mapped the range of tree architecture using terrestrial laser scanning data. This was done by scanning trees and forests from multiple locations, fitting cylinders to the raw point cloud data and then extracting architectural metrics from those cylinder models. … Continue reading
2nd Jun 2019
We have evaluated the history, current situation and trends of forest fragmentation in China, and summarised their effects on biodiversity.
Most studies exploring habitat fragmentation effect on biodiversity were conducted at the local or regional level. These studies generally ignored background information (e.g. history, drivers and dynamics) of forest fragmentation which is critical for biodiversity conservation at large scales (e.g. national scale). … Continue reading
2nd Jun 2019
Here we report the recent discovery of the world’s tallest tropical tree (Shorea faguetiana), possibly the world’s tallest angiosperm (flowering plant), located in the rainforests of Sabah, Malaysian Borneo. In addition, we provide a novel three-dimensional exploration of the dimensions of this remarkable tree and use these data to speculate on what drives the limits of tree height. Through consideration of both mechanical (risk of wind damage) and ecophysiological constraints we argue that this tree is close to the maximum height possible for angiosperms, around 100 m … Continue reading
2nd Jun 2019
We have quantified the effect of habitat fragmentation on diversity patterns of plants and seed dispersers in an artificial island archipelago, and concluded that differential responses of seed dispersers to habitat fragmentation may lead to pervasive shifts in the plant community structure of regenerating forest fragments.
Traditional studies generally consider habitat fragmentation as a driver of downsizing of plant seeds due to the disappearance of large seed dispersing vertebrates. However, most of these studies focuses on old‐growth forests, and much less is known about … Continue reading
13th May 2019
We have assessed the quality of three dimensional forest models produced from drone surveys, and conclude that concerns about their quality for canopy height and carbon measurement are unjustified. The rise of drones has been explosive. Rapid advances in technology and decreases in price have resulted in products that can be used off-the-shelf to survey forests. Drones take overlapping photos that can be analysed using a piece of software, called structure from motion, that finds the distinctive ‘features’ shared between overlapping images. The location of these so called ‘tie-points’ is then triangulated to build a three-dimensional model of the forest. … Continue reading
5th April 2019
We have quantified the temperature difference between sites within forests and outside, for the first time across the globe. Measurements occurred at 98 locations spread across five continents, in the tropics, temperate zone and northern boreal forests. The data show that the maximum temperature in forests is , on average across the globe, 4 degrees lower than outside forests.
With their foliage and branches in the canopy, trees create a thermal isolating layer above the forest, cooling the understory when ambient temperatures are hot and warming the understory when ambient temperatures are cold. … Continue reading
30th Jan 2019
Organisms experience climate at a small scale, where the topography and the vegetation cause microclimates that vary greatly in space and time. The difference in temperature between north and south facing slopes of a mole hill on a hot summer’s day in Europe, for example, is comparable to the temperature difference between the Mediterranean and Scotland. Microclimates are often neglected in ecology and evolution, despite mounting evidence that microclimates matter for ecosystem dynamics and processes, such as the response of organisms to climate change. A key impediment has been the lack of spatial data to map microclimatic variation over large spatial scales and over time. … Continue reading