Woodland Trees Research Articles

Distinct phases of natural landscape dynamics and intensifying human activity in the central Kenya Rift Valley during the past 1300 years

Socio-ecological stresses currently affecting the semi-arid regions of equatorial East Africa are driving environmental changes that need to be placed in a proper context of long-term human-climate-landscape interaction. Here we present a detailed reconstruction of past human influences on the landscape of the central Kenya Rift Valley, against the backdrop of natural climate-driven ecosystem dynamics over the past 1300 years. Proxy records of vegetation dynamics (pollen), animal husbandry (fungal spores), biomass burning (charcoal) and soil mobilization (clastic mineral influx) extracted from the continuous depositional archive of Lake Bogoria reveal six distinct phases of human activity. From ca 700 to 1430 CE, strong primary response of savanna woodland ecotonal vegetation to climatic moisture-balance variation suggests that anthropogenic influence on regional ecosystem dynamics was limited. The first unambiguous ecological signature of human activities involves a mid-15th century reduction of woodland/forest trees followed by the appearance of cereal pollen, both evidence for mixed farming. From the mid-17th century, animal husbandry became a significant ecological factor and reached near-modern levels by the mid-19th century, after severe early-19th century drought had substantially changed human-landscape interaction. A short-lived peak in biomass burning and evidence for soil mobilization in low-lying areas of the Bogoria catchment likely reflects the known 19th-century establishment of irrigation agriculture, while renewed expansion of forest and woodland trees reflect the return of a wetter climate and abandonment of other farmland. Since the mid-20th century, the principal signature of human activity within the Lake Bogoria catchment is the unprecedented increase in clastic sediment flux, reflecting widespread soil erosion associated with rapidly intensifying land use.

Формирование подстилки пойменных лесных биогеоценозов с участием Acer negundo L.

The article presents the results of the influence of box elder (Acer negundo L.) litterfall on the forest litter formation in floodplain forest communities. The research object was plant litter collected from different sites of phytogenic fields of A. negundo natural stands growing in the floodplain of the Tom River. Sampling was carried out according to the three types of crown density. The outer zone of scattered trees was chosen as a control sample. The vegetation cover was described, and the dominant plant species and their total projective cover were determined within the subcrown, near-front and outer zones of the tree phytogenic field. Just before the research analytical samples were isolated; they were dried to air-dry condition and weighed in order to determine the proportion of each plant fraction. Content of polyphenolic compounds and lignin was determined in the samples. The results’ analysis had shown that the crown density of Acer negundo L. population, as well as the content of mineral and organic compounds of plant litter, influences the formation of floodplain forest communities’ litter. The most intensive mineralization of litter in the soil, especially in the subcrown zone, is found under scattered trees in sparse woodland. Probably this is due to the increased content of nutrients and total absorbed bases, as well as a higher phytomass accumulation, and minimum content of polyphenols and lignin, in comparison with the forest litter of trees from the other studied groups. The research results can be used for the monitoring of natural ecosystems. For citation: Tsandekova O.L., Ufimtsev V.I. Formation of Floodplain Forest Biogeocenosis Litter with the Participation of Acer negundo L. Lesnoy Zhurnal [Forestry Journal], 2019, no. 3, pp. 73–81. DOI: 10.17238/issn0536-1036.2019.3.73Funding: The research was carried out within the framework of the state assignment of the Federal Research Center of Coal and Coal Chemistry of the Siberian Branch of the RAS (project no. 0352-2019-0015)

Management implications of tree growth patterns in miombo woodlands of Zambia

Brachystegia-Julbernardia (miombo) woodlands of east and southern Africa are divided into dry (<1000 mm annual rainfall) and wet (>1000 mm). These woodlands first became established about 14,500 years ago. Since the migration of the Bantu people 5000 years ago, miombo woodlands have experienced widespread degradation and deforestation. There is little long-term data on tree growth and forest productivity for miombo woodlands and yet such data are required for the proper management of these woodlands. This study used tree growth data from 35 temporary plots in regrowth of 5–49 years old, and six permanent sample plots (PSPs) in old growth forest, which were monitored over a 28-year period (1990–2018). These data were used to investigate tree diameter growth and develop models of forest dynamics in wet and dry miombo woodlands. The study found that variations in tree diameter and stand basal area increments are strongly driven by stand age, tree size and density and that growth rates are higher in wet than dry miombo. Overall miombo woodland trees grew slowly at a rate of 0.34–0.50 cm yr−1 in re-growth areas. Most of the species in uneven-aged old-growth stands in dry miombo grew by 0.15 cm yr−1 with no significant annual differences although variations among conspecifics were large. Models predicted tree diameter increments of 0.10–0.24 cm yr−1 for stands of 100 years old. Transitions from one 5-cm diameter class to the next was estimated to take over 20 years and significant shifts in stand tree diameter distribution curves require over 25 years because of the low annual diameter increments. Stand responses to degradation varied from site to site and were driven by the number of saplings transiting into small diameter size classes. On the temporary regrowth plots basal areas averaged 7.1 m2 ha−1 and 9.9 m2 ha−1 in dry and wet re-growth miombo, respectively, with positive increments estimated at 0.40 m2 ha−1 yr−1 in dry miombo and 0.53 m2 ha−1 yr−1 in wet miombo. By contrast, average basal area increment on old-growth PSPs was negative, at −0.26 m2 ha−1 yr−1 over the 1990–2018 period, due to cutting and fire damage. Such drivers of forest degradation need to be controlled, especially in old-growth miombo, to maintain forest health and prevent decline in biomass.

Costatamins A – C, new 4-phenylcoumarins with anti-inflammatory activity from the Australian woodland tree Angophora costata (Myrtaceae)

The bioassay-guided isolation of new anti-inflammatory metabolites from the Australian Indigenous plant Angophora costata led to the discovery of three new 4-phenylcoumarins, costatamins A – C (1–3). The structures were determined by detailed spectroscopic analysis. Costatamins A – C were evaluated for their inhibitory effects on (a) NO production and (b) TNF-α release in RAW 264.7 macrophages, displaying an IC(50) value of 20–30 μg/mL for both the inflammatory markers.

Fever tree woodlands at risk from intensification of land management activities associated with human and wildlife utilization

Losses of acacia woodlands have been reported throughout eastern and southern Africa. Of particular concern is the loss of fever tree (Vachellia xanthophloea) woodlands along the riparian areas of lakes which may result in the loss of important terrestrial and aquatic ecosystem services. For example, the Lake Naivasha basin in Kenya has endured considerable population growth and associated changes in land management with potential consequences for fever tree woodlands. This study assessed how fever tree woodland integrity differed with varying degrees of human and wildlife disturbances among surrounding land use management types. A field survey of fever tree woodlands suggest that land management types influenced degrees of human and wildlife disturbances, with settlement areas having significantly more human disturbance and conservation areas having significantly more wildlife disturbance. Furthermore, while land management type did not significantly influence the stem sizes of fever trees, it did influence the condition of woodland crown and ground covers. Settlement areas with high human disturbance were correlated with healthier crown covers (a possible artifact of the removal of dead or dying crown for fuelwood) while conservation areas with high wildlife disturbance were correlated with less healthy crown covers in smaller trees (<45 cm diameter at breast height) that were not killed but stunted by wildlife browsing. Settlement areas were dominated by more but less diverse ground cover while conservation areas were correlated with less but more diverse ground cover. While fever trees show resilience to multiple disturbances, the early warning of changes to the woodlands imply that the future of the fever tree woodlands is at risk and that limits to the encroachment of land management activities into the fever tree woodlands should be established.

Effects of seed viability and pre-treatments on seed germination of two indigenous species—Strychnos cocculoides Baker and Guibourtia coleosperma (Benth.) Leonard in Namibia

Strychnos cocculoides Baker (Monkey orange) and Guibourtia coleosperma (Benth.) Leonard (False mopane) are two socio-economically important indigenous species for rural communities in the northern regions of Namibia. The exploitation of these indigenous species is causing rapid declines in the goods and services produced. In addition, nursery experiments to assist the germination of these indigenous woodland trees are limited. This study aimed at investigating the effects of six pre-treatments [control, cold water (15 °C), warm water (50 °C), hot water (90 °C), scarification and chemical with 32% HCl] on the seed germination of both species. Prior to the pre-treatments, sample seeds were tested for viability using the tetrazolium and rag doll tests. This was conducted to determine whether the seeds used in this study were viable and had a germination potential. For both species, over 80% seeds were viable with the tetrazolium test. Germination results indicated a significant difference between the six pre-treatments, which was more pronounced for S. cocculoides than for G. coleosperma. For S. cocculoides seeds, warm water (80%), cold water (70%) and control (untreated seeds) (63%) yielded greater percentages of germination than hot water (40%), scarification (3%) and HCI-chemical (0%) after 7 weeks of germination. For G. coleosperma seeds, warm water (83%), cold water (80%), control (80%) and hot water (70%) produced the highest percentage of germination, compared to chemical (67%) and scarification (67%) pre-treatments. The control, cold and warm water pre-treatments showed germination of S. cocculoides seeds within 3 weeks of sowing, while for other treatments, seeds only germinated 4 weeks after sowing. Guibourtiacoleosperma untreated and warm water-treated seeds germinated earlier (week 2) compared to the other pre-treatments, for which germination only occurred during week 3. Therefore, the study recommends warm water as an ideal pre-treatment to promote germination in S. cocculoides and G. coleosperma species. Potential future studies could investigate effect of different temperatures and photoperiods on the germination percentage of the two species.

Estimating net biomass production and loss from repeated measurements of trees in forests and woodlands: Formulae, biases and recommendations

There is widespread interest in ensuring that assessment and knowledge of changes in forest biomass, and associated carbon gains or losses, are accurate and unbiased. Repeated measurements of individually-marked trees in permanent plots permit the estimation of rates of biomass production by tree growth and recruitment and of loss from mortality. But there are challenges, for example, simple estimates of production rate (i.e., the sum of biomass gain by growth of surviving trees and new recruits divided by census duration) decline as the census interval increases due to unrecorded growth. Even if we allow for these unobserved changes, additional biases may arise due to the non-independence of growth and mortality and to the heterogeneity and compositional changes within the forest. Here we examine these issues and demonstrate how problems can be minimized. We provide and compare alternative approaches to estimate net biomass production and loss from tree growth and mortality. Under the assumption that specific rates of biomass production and loss, i.e., turnover, are constant over time, we derive estimates of absolute biomass turnover rates that are independent of census duration. We show census-interval dependence of simple turnover rates grows with increasing specific turnover rates. While the time-dependent bias in simple estimates has previously been suggested to increase in proportion to the square of production, we show this relationship is approximately linear. Correlations between stem growth and mortality do not influence our estimates. We account for biomass gain by recruited stems without discounting their initial biomass in production estimates. We can reduce additional biases by accounting for differences in turnover among subpopulations (such as species, sites) and changes in their abundances. We provide worked examples from four forests covering a range of conditions (in Indonesia and Japan) and show the effects of accounting for these biases. For example, over five years in an Indonesian rain forest, simple estimates and instantaneous estimates neglecting species heterogeneity underestimated production by 4.9% and 1.6%, respectively when compared to comprehensive (instantaneous species-structured) estimates.

Grass Functional Traits Differentiate Forest and Savanna in the Madagascar Central Highlands

Grassland, woodland and forest are three key vegetation types that co-occur across the central highlands of Madagascar, where the woodland has historically been considered as degraded forest. Here, we use grass functional traits to inform our understanding of the biogeography of Malagasy vegetation and the differentiation of vegetation types in the region. We sampled grass community composition at 56 sites across the central highlands of Madagascar spanning grassland, woodland and forest. We selected seven functional traits known to correlate with different aspects of life history collated via GrassBase (habit, culm type, physiology, leaf consistency, plant height, leaf width and leaf length) for the 71 constituent species. Via analyses of the beta diversity, rank abundance, functional dispersion, functional group richness and community phylogenetic structure of grassland communities, we differentiate these vegetation types using plant functional traits. Grassland and woodland are highly similar in grass species composition and dominated by the same species (Loudetia simplex, Trachypogon spicatus and Schizachyrium sanguineum). In contrast, forest grass species composition significantly differs from both grassland and woodland. Consistent with these species composition patterns, the vegetation types can be distinguished based on physiology, culm type and leaf consistency. Forests harbour primarily C3 grasses, which are almost invariably laterally spreading with herbaceous leaves. In contrast, both grassland and woodland species are predominantly tall, caespitose C4 grasses with coriaceous leaves. Forest grasses are phylogenetically clustered and less diverse than the grassland and woodland communities. Further, we sampled bark thickness of the common woody species occurring in the woodland and forest of the region and found that the relative bark thickness of the woodland tree species was significantly greater than that of forest species from the same genus. We found that the functional traits and architecture of grasses diverge strongly between forest and the grassland-woodland mosaic. We conclude that the woodlands, primarily dominated by Uapaca bojeri Baill., are a form of savanna and not forest as has been previously suggested.

Ninety years of change on the TGB Osborn Vegetation Reserve, Koonamore: a unique research opportunity

The TGB Osborn Vegetation Reserve, on Koonamore station in the NE pastoral area of South Australia, is the longest-running vegetation monitoring project of its type in Australia. In 1925, a 4-km2 rectangle in a heavily overgrazed area was fenced to exclude rabbits and sheep, and permanent quadrats and photo-points set up to record changes. The area is predominantly chenopod shrubland, with an open woodland tree layer. After the initial elimination of rabbits, control slackened and rabbit numbers increased until the 1970s, when intense elimination efforts resumed, together with the arrival of myxomatosis and rabbit haemorrhagic disease viruses. Consequently, the reserve has had 50 years without sheep, followed by 40 years virtually without either sheep or rabbits. Changes over that time have been very striking, and they have been recorded regularly via mapped quadrats and photopoints. The objective of this paper is to highlight opportunities for making use of this database for researching several interesting ecological questions.

Draft Genome Sequence for the Tree PathogenPhytophthora plurivora

Species from the genus Phytophthora are well represented among organisms causing serious diseases on trees. Phytophthora plurivora has been implicated in long-term decline of woodland trees across Europe. Here we present a draft genome sequence of P. plurivora, originally isolated from diseased European beech (Fagus sylvatica) in Malmö, Sweden. When compared with other sequenced Phytophthora species, the P. plurivora genome assembly is relatively compact, spanning 41 Mb. This is organized in 1,919 contigs and 1,898 scaffolds, encompassing 11,741 predicted genes, and has a repeat content of approximately 15%. Comparison of allele frequencies revealed evidence for tetraploidy in the sequenced isolate. As in other sequenced Phytophthora species, P. plurivora possesses genes for pathogenicity-associated RXLR and Crinkle and Necrosis effectors, predominantly located in gene-sparse genomic regions. Comparison of the P. plurivora RXLR effectors with orthologs in other sequenced species in the same clade (Phytophthora multivora and Phytophthora capsici) revealed that the orthologs were likely to be under neutral or purifying selection.

Dendrochronological assessment of British veteran sweet chestnut (Castanea sativa) trees: Successful cross-matching, and cross-dating with British and French oak (Quercus) chronologies

Across Britain and continental Europe there are many ancient Castanea sativa trees of great significance for natural and cultural heritage, yet scant assessment has been made of them for dendrochronological information. This paper describes the dendrochronological analysis of 28 Castanea sativa trees (veteran historic trees, forest trees and coppice stems) sampled from 15 sites in southern Britain: 56 growth-ring sequences were collected for analysis, by boring living trees and by cutting transverse sections from dead fallen trees and previously cut stumps. Twenty-three single-tree sequences from 14 sites were cross-matched (t ≥3.5) and then cross-dated with 17 oak Quercus reference chronologies from England and northern France: a Castanea sativa master chronology spanning AD 1660–2014 has been created. The results demonstrate the viability of dendrochronological analysis of Castanea sativa wood; and confirm that Castanea sativa can be cross-dated with oak Quercus reference chronologies, inter-regionally and inter-nationally. The findings provide the potential means for dating Castanea sativa timbers sampled from palaeoenvironmental and historical contexts. The extraction of sawn sections from long-dead (up to 60 years in this study) trees and stumps is proven to be a reliable method for dating veteran trees in cultural landscapes and ancient woodlands; and for revealing the growth history of historic/iconic trees. The germination dates calculated for the Castanea sativa trees in this study span the period AD 1640–1943. The inaccuracy of estimating veteran Castanea sativa tree ages from girth measurements is highlighted.

A monitoring toolkit for banksia woodlands: comparison of different scale methods to measure recovery of vegetation after fire

AbstractHere, we compare the efficiency and accuracy of remote sensing and plot‐based methods for measuring vegetation cover for the understory and canopy of banksia woodland in an urban area of Western Australia. Methods compared were visual estimation, foliage cover computation from photographs, satellite imagery and aerial photographs. Observations and images from 1 m2, 100 m2 and 625 m2 quadrats measured cover of small plants, understory plants and trees respectively. Aerial photography and satellite imagery allowed the number, height and cover of trees to be estimated in 625 m2 and 1 ha plots. The accuracy of methods was compared using a 28 month time series commencing before and after an intense bushfire that removed all foliage cover. Directly comparable methods were in close agreement and in combination allowed plant recovery to be quantified in great detail. Visual estimation of cover in the field was time‐consuming but necessary to measure the contribution of individual species. Visual estimates from 1 m2 downward photos allowed functional groups of plants to be measured. The number of green pixels selected manually in photographs confirmed that cover calculated from ground‐based photographs using algorithms was accurate, except when cover was very low. We developed a new algorithm for computing cover from photographs that was accurate at low cover (Gperc). Canopy cover estimation by algorithm from upward photographs was subject to more errors, requiring exclusion of some images. Landsat satellite images allowed the impacts of severe drought and previous fires to be identified against a background of relatively consistent seasonal variations since 1988. Aerial photographs from 1953 onwards showed gradual recolonisation by banksia woodland trees over 60 years following tree felling. These methods provide a toolkit for monitoring vegetation recovery after disturbance and baseline data for monitoring banksia woodland. This toolkit should also be suitable for most other plant communities.

Distributed Plant Hydraulic and Hydrological Modeling to Understand the Susceptibility of Riparian Woodland Trees to Drought‐Induced Mortality

AbstractThe mechanistic understanding of drought‐induced forest mortality hinges on improved models that incorporate the interactions between plant physiological responses and the spatiotemporal dynamics of water availability. We present a new framework integrating a three‐dimensional groundwater model, Parallel Flow, with a physiologically sophisticated plant model, Terrestrial Regional Ecosystem Exchange Simulator. The integrated model, Parallel Flow‐Terrestrial Regional Ecosystem Exchange Simulator, was demonstrated to quantify the susceptibility of riparian cottonwoods (Populus angustifolia, Populus deltoides, and native hybrids) in southwestern Canada to sustained atmospheric drought and variability in stream flow. The model reasonably captured the dynamics of soil moisture and evapotranspiration in both wet and dry years, including the resilience of cottonwoods despite their high vulnerability to xylem cavitation. Unrealistic predictions of mortality could be generated when ignoring lateral groundwater flow. Our results also illustrated a mechanistic linkage between streamflow and cottonwood health. In the absence of precipitation, normal streamflow could sustain 94% of cottonwoods, and higher streamflows would be required to sustain all of the floodplain cottonwoods. Further, the risk of mortality was mediated by plant hydraulic properties. These results underpin the importance of integrating groundwater processes and plant hydraulics in order to analyze the forest response to sustained severe drought, which could increase in the future due to climate change combined with increasing river water withdrawals.

Biological Flora of the British Isles: Ulmus glabra

Abstract This account presents information on all aspects of the biology of Ulmus glabra Hudson (wych elm) that are relevant to understanding its ecological characteristics and behaviour. The main topics are presented within the standard framework of the Biological Flora of the British Isles: distribution, habitat, communities, responses to biotic factors, responses to environment, structure and physiology, phenology, floral and seed characters, herbivores and disease, history and conservation. Ulmus glabra is a large forest tree, and often an important canopy tree in ancient and semi‐natural woodlands. It is primarily native to the north and west of Britain and much of mainland Europe. It is the only elm native to Ireland. It is the most distinct of the British elms in that it rarely suckers and sets abundant viable seed. Although found on limestone screes and cliffs, and hedgerows, it is primarily a woodland tree, especially on moist, basic soils. In many secondary woodlands, it often co‐occurs with Acer pseudoplatanus and has ecological needs that are similar to Fraxinus excelsior. Ulmus glabra has clusters of c. 25 hermaphrodite flowers appearing before the leaves on previous year’s growth. Seeds are wind‐dispersed, falling in April to July, but remain viable for only a few days. Nevertheless, seedling establishment can be abundant. Hybridisation with other northern European elms is common but hybrids are notoriously difficult to identify and therefore probably under‐recorded. The health and survival of wych elm in Europe has been seriously compromised since the 1970s due to Dutch elm disease caused by the fungus Ophiostoma novo‐ulmi, transmitted by elm bark beetles (Scolytus spp.). To the south of its Scottish stronghold, many elms are reduced to small trees regrowing from basal sprouts or seeds. These trees tend to be reinfected once trunk diameter exceeds 10 cm. Fortunately for its long‐term survival, seed production usually begins a number of years before they are reinfected.

Seasonal changes in plant-water relations influence patterns of leaf display in Miombo woodlands: evidence of water conservative strategies.

Water availability has frequently been linked to seasonal leaf display in seasonally dry ecosystems, but there have been few ecohydrological investigations of this link. Miombo woodland is a dominant seasonally dry tropical forest ecosystem type in southern Africa; however, there are few data on the relationship between seasonal dynamics in plant-water relations and patterns of leaf display for Miombo woodland. Here we investigate this relationship among nine key Miombo woodland tree species differing in drought tolerance ability and leaf phenology. Results of this study showed that seasonal patterns of leaf phenology varied significantly with seasonal changes in stem water relations among the nine species. Leaf shedding coincided with the attainment of seasonal minimum stem water potential. Leaf flush occurred following xylem rehydration at the peak of the dry season suggesting that endogenous plant factors play a pivotal role in seasonal leaf display in this forest type. Drought-tolerant deciduous species suffered significantly higher seasonal losses in xylem hydraulic conductivity than the drought-intolerant semi-evergreen tree species (P < 0.05). There was a significant and positive correlation between species drought tolerance index and species' seasonal loss in hydraulic conductivity (P < 0.05), confirming the ecological role of long-distance xylem transport in this seasonally dry tropical forest. Our results reveal that water stress in seasonally dry tropical forests selects for water conservative traits that protect the vulnerable xylem transport system. Therefore, seasonal rhythms in xylem transport dictate patterns of leaf display in seasonally dry tropical forests.

"Reduction of tree cover in West African woodlands and promotion in semi-arid farmlands".

Woody vegetation in farmland acts as a carbon sink and provides ecosystem services for local people, but no macro-scale assessments of the impact of management and climate on woody cover exists for drylands. Here we make use of very high spatial resolution satellite imagery to derive wall-to-wall woody cover patterns in tropical West African drylands. Our study reveals a consistently high woody cover in farmlands along all semi-arid and sub-humid rainfall zones (16%), on average only 6% lower than in savannas. In semi-arid Sahel, farmland management increases woody cover to a greater level (12%) than found in neighbouring savannas (6%), whereas farmlands in sub-humid zones have a reduced woody cover (20%) as compared to savannas (30%). In the region as a whole, rainfall, terrain and soil are the most important (80%) determinants of woody cover, while management factors play a smaller (20%) role. We conclude that agricultural expansion cannot generally be claimed to cause woody cover losses, and that observations in Sahel contradict simplistic ideas of a high negative correlation between population density and woody cover.

DOES THE CUTTING OF MIOMBO TREE SPECIES FOR CHARCOAL PRODUCTION DIRECTLY CAUSE DEFORESTATION? A CASE STUDY OF KAPIRI MPOSHI AREA, CENTRAL ZAMBIA

This study assessed the response of miombo woodland tree species to the impact of charcoal production along the Kabwe – Ndola highway in Kapiri Mposhi district, central Zambia and covered the period 2013 - 2017. The main objective of the study was to determine whether all tree species harvested for charcoal production regenerated to answer the question, does tree cutting for charcoal production directly cause deforestation? Factors considered were species cut for charcoal production, height above ground at which the tree was cut, cutting angle and aspect, stump thickness, season of cutting and the number and location of saplings. Vegetation assessments were carried out in 20 m x 20 m quadrats laid out at each sample point in which only trees ≥ 30cm circumference were considered. Height of the stump above ground was taken in cm and cut angle determined by placing a carpenters’ square at the lowest end of the cut across the stump to form a perfect horizontal line. Evidence of regeneration through coppicing was carried out by visually examining stumps for regeneration. Results obtained showed that all species regenerated after cutting although only ten (10) species were commonly used in charcoal production mainly of the genera Brachystegia and Julbernardia. The mean stump height in cm of all tree species was 48 cm. Two categories of cut angle classes were common, acute angle (1800) 60 % (n = 708 stumps) and straight/flat angle 36 % (n = 425 stumps), obtuse angle 3 % (n= 35 stumps) and other 1% (n = 12 stumps). A difference was recorded in the coppicing period. Species sprouted within four weeks (at least showing a bud) between August and November and during the rainy season but took more than four weeks in ≥ 75% of the cases during the cold season May – July. It was concluded that the cutting of trees for charcoal production was not the direct cause of deforestation, but it was perhaps the greatest agent as more than 80% of the sites cleared for charcoal production were occupied by human settlements at least by end of the second year. Further studies are required to investigate species characteristics that may influence regeneration in addition to moisture and soil nutrients.

Ground-based and LiDAR-derived measurements reveal scale-dependent selection of roost characteristics by the rare tree-dwelling bat Barbastella barbastellus

Abstract Bats use roosts for protection, sociality and reproduction. Lack of knowledge regarding the specific roost preferences of tree-dwelling bats means that roosts are regularly removed from woodland during felling and thinning interventions, even when woodlands are managed to promote biodiversity. The often-unintentional loss of roosts this way continues to constrain efforts to conserve many rare bat species. We investigated roost selection by the barbastelle Barbastella barbastellus in fragmented oak woodlands in southwest England. Twenty-nine bats were radio tracked to 44 tree roosts between 2007 and 2015. Twenty-four different characteristics of roosts were measured using a combination of ground-based field surveys and airborne light detection and ranging (LiDAR) imagery, and roost characteristics were compared with those of random trees to determine selection. Bats selected trees in ancient semi-natural broadleaved woodland over other woodland habitat types. Standing dead oak (Quercus spp.), while scarce, was positively selected over other tree types and supported significantly more suitable roost cavities. Roost selection was most strongly influenced by the number of cavities present on a tree and the openness of the canopy around the tree. The height of roost cavities and distance to water were also important features that influenced selection. Pregnant and lactating bats switched roosts less frequently than post-lactating and nulliparous bats and selected cavities higher on trees, most likely to facilitate the development of offspring and reduce the risk of predation. Old growth woodland is vitally important to barbastelles and so the preservation and restoration of these habitats should be a conservation priority. While standing dead trees supported more preferred roost cavities than other tree types, our findings indicate that any tree supporting a suitable cavity may be used as a roost, irrespective of the size, condition or species, and should be retained wherever possible. Promoting the natural succession of younger woodland will help to deliver additional sustained benefits in the future.

Incorporation of Stem Water Content into Vegetation Optical Depth for Crops and Woodlands

Estimation of vegetation water content (VWC) by optical remote sensing improves soil moisture retrievals from passive microwave radiometry. For a variety of vegetation types, the largest unknown for predicting VWC is stem water content, which is assumed to be allometrically related to the water content of the plant canopy. For maize and soybean, measured stem water contents were highly correlated to canopy water contents, so VWC was calculated directly from the normalized difference infrared index (NDII), which contrasts scattering at near-infrared wavelengths with absorption of shortwave infrared wavelengths by liquid water. Woodland tree height is linearly related to woody stem volume, and hence to stem water content. We hypothesized that tree height is positively correlated with canopy water content, and thus with NDII. Airborne color-infrared imagery was acquired at two study areas in a mixed agricultural and woodland landscape, and photogrammetric structure-from-motion point clouds were derived to estimate tree heights. However, estimated tree heights were only weakly correlated with measured data acquired for validation. NDII was calculated from Landsat 8 Operational Line Imager (30-m pixel) and WorldView-3 (7.5 m pixel); but contrary to the hypothesis, NDII was not correlated with woodland tree height. Lastly, the interaction of woodland and crops stem water contents on total VWC in a mixed landscape were simulated for 2 days, one in the early summer and one in the late summer. VWC for the region varied from 2.5 to 3.0 kg m−2, which was just under a threshold for accuracy for soil moisture retrievals using Coriolis WindSat. Woodland tree height should be included as an ancillary data set along with land cover classification for soil moisture retrieval algorithms.

Allometric models for managing lowland miombo woodlands of the Beira corridor in Mozambique

Appropriate allometric models are urgently needed to assess the status and changes in biomass and carbon of the trees in miombo woodlands occupying large geographical areas in Mozambique. This study developed two new and interchangeable allometric models for estimating total above-ground biomass (AGB) of lowland miombo woodlands in the Beira corridor, central Mozambique, based on stem diameter at breast height (DBH) and stump diameter (SDI). The Beira corridor study area covers approximately 29,000 km2, of which about three-quarters is lowland miombo woodland. The SDI-based model is proposed principally for estimating total AGB (stem, branches, foliage) of harvested trees/shrubs when diameter cannot be measured at breast height, and thus to reconstruct the former biomass in forests subjected to logging, or clear-cutting for agriculture.The DBH-based model and SDI-based model were fitted using data on a destructive sample of 155 trees, which were representative of tree sizes (diameter and height) and tree species in the Beira corridor area. The following allometric models were developed: DBH-based model [tDW (kg tree−1) = 0.1754 * (DBH) 2.3238], with prediction performance, i.e. adjusted R-squared 98–99%; and SDI-based model [tDW (kg tree−1) = 0.08495 * (SDI) 2.3987], with prediction performance 86–96%. Carbon comprises 50% of biomass. Both the DBH- and SDI-based models can be used for estimating total AGB of lowland miombo woodlands with a high degree of reliability, based on field inventory within the Beira corridor region. Evaluation of the mathematical and statistical credibility of these models, which was carried out on the construction dataset (verification procedure) and independent dataset (validation procedure), gave satisfactory results. Moreover, when applied on our data, these models were more appropriate for the Beira corridor than allometric models found in the literature. However, application of both models should be restricted to the lowland miombo type in the Beira corridor, not mountain miombo.