Modelling bark volume for six commercially important tree species in France: assessment of models and application at regional scale

2021 ◽  
Vol 78 (4) ◽  
Author(s):  
Rodolphe Bauer ◽  
Antoine Billard ◽  
Frédéric Mothe ◽  
Fleur Longuetaud ◽  
Mojtaba Houballah ◽  
...  
Keyword(s):  
Tree Species ◽  
Regional Scale ◽  
Commercially Important

Pollen treatment for mutation induction in Eucalyptus globulus ssp. globulus (Myrtaceae)

2006 ◽  
Vol 54 (1) ◽  
pp. 65 ◽  
Author(s):  
L. J. McManus ◽  
J. Sasse ◽  
C. K. Blomstedt ◽  
G. Bossinger
Keyword(s):  
Tree Species ◽  
Eucalyptus Globulus ◽  
Frost Tolerance ◽  
Mutation Induction ◽  
Crop Species ◽  
Integral Role ◽  
Fruit Abortion ◽  
Commercially Important ◽  
Reproductive Cycles ◽  
Short Time

Mutation induction has played an integral role in the improvement of most commercially important crop species but has not been successfully applied to tree species because of their long reproductive cycles which hinder the use of the traditional seed-treatment approaches. Treatment of pollen with a chemical mutagen prior to pollination will, theoretically, allow stable, heterozygous mutant trees to be produced in a relatively short time and might facilitate mutagenesis of tree species. As the first step in testing this hypothesis, a controlled-pollination trial with chemically treated pollen was conducted in Eucalyptus globulus ssp. globulus (Labill.). Assessment of fruit, seed and seedlings from more than 500 pollinations associated mutagenic treatment of pollen with a significant reduction in seed set. Non-significant increases in capsule (fruit) abortion, the inhibition of seed germination and the incidence of aberration in seedlings were also noted. We argue that pollen treatment may be a useful means of producing Eucalyptus mutants with variation in flowering time, salinity and frost tolerance, lignification and other traits of scientific and economic importance.

scholarly journals On the rebound: soil organic carbon stocks can bounce back to near forest levels when agroforests replace agriculture in southern India

2015 ◽  
Vol 2 (2) ◽  
pp. 871-902 ◽  
Author(s):  
H. C. Hombegowda ◽  
O. van Straaten ◽  
M. Köhler ◽  
D. Hölscher
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Tree Species ◽  
Regional Scale ◽  
Clay Fraction ◽  
Carbon Stocks ◽  
Southern India ◽  
Reference Plot ◽  
Soc Stock ◽  
Soc Stocks

Abstract. Tropical agroforestry has an enormous potential to sequester carbon while simultaneously producing agricultural yields and tree products. The amount of soil organic carbon (SOC) sequestered is however influenced by the type of the agroforestry system established, the soil and climatic conditions and management. In this regional scale study, we utilized a chronosequence approach to investigate how SOC stocks changed when the original forests are converted to agriculture, and then subsequently to four different agroforestry systems (AFSs): homegarden, coffee, coconut and mango. In total we established 224 plots in 56 plot clusters across four climate zones in southern India. Each plot cluster consisted of four plots: a natural forest reference plot, an agriculture reference and two of the same AFS types of two ages (30–60 years and > 60 years). The conversion of forest to agriculture resulted in a large loss the original SOC stock (50–61 %) in the top meter of soil depending on the climate zone. The establishment of homegarden and coffee AFSs on agriculture land caused SOC stocks to rebound to near forest levels, while in mango and coconut AFSs the SOC stock increased only slightly above the agriculture stock. The most important variable regulating SOC stocks and its changes was tree basal area, possibly indicative of organic matter inputs. Furthermore, climatic variables such as temperature and precipitation, and soil variables such as clay fraction and soil pH were likewise all important regulators of SOC and SOC stock changes. Lastly, we found a strong correlation between tree species diversity in homegarden and coffee AFSs and SOC stocks, highlighting possibilities to increase carbon stocks by proper tree species assemblies.

scholarly journals Different mycorrhizal nutrient acquisition strategies shape tree species competition and coexistence dynamics

2021 ◽  
Author(s):  
Michael E Van Nuland ◽  
Po-Ju Ke ◽  
Joe Wan ◽  
Kabir G Peay
Keyword(s):  
Tree Species ◽  
Mycorrhizal Fungi ◽  
Large Scale ◽  
Resource Competition ◽  
Regional Scale ◽  
N Fertilization ◽  
Nutrient Acquisition ◽  
Soil Microbiome ◽  
Biogeographic Patterns ◽  
Acquisition Strategies

Mycorrhizal fungi with different nutrient acquisition strategies influence the functional separation among plant species. This might drive resource competition dynamics that cumulatively impact tree species coexistence, but few manipulative experiments have directly tested this. Combining surveys and experiments in a modern coexistence theory framework, we tested how variation in mycorrhizal strategies and nutrient conditions affect competitive outcomes between co-occurring ectomycorrhizal (EM) and arbuscular mycorrhizal (AM) tree species. The dependency on EM symbioses increased with latitude and nitrogen (N) limitation, matching global trends. Host-specific soil microbiome conditioning and N fertilization combined to qualitatively affect coexistence outcomes. Lower N conditions favored EM over AM trees, but N fertilization reversed this outcome for southern species, consistent with regional-scale forest mycorrhizal transitions. As the magnitude and outcome of microbially-mediated competition depends on mycorrhizal differentiation and soil nutrient availability, this strongly supports the importance of mycorrhizal symbioses in driving large-scale biogeographic patterns of tree species.

scholarly journals Assessing the protective role of alpine forests against rockfall at regional scale

2020 ◽  
Vol 139 (6) ◽  
pp. 969-980
Author(s):  
Christian Scheidl ◽  
Micha Heiser ◽  
Sonja Vospernik ◽  
Elisabeth Lauss ◽  
Frank Perzl ◽  
...  
Keyword(s):  
Protective Effect ◽  
Forest Fires ◽  
Tree Species ◽  
Structural Parameters ◽  
Regional Scale ◽  
Reduction Factor ◽  
Stem Number ◽  
Forest Stands ◽  
Rockfall Hazard ◽  
Hazard Reduction

Abstract Worldwide, mountain forests represent a significant factor in reducing rockfall risk over long periods of time on large potential disposition areas. While the economic value of technical protection measures against rockfall can be clearly determined and their benefits indicated, there is no general consensus on the quantification of the protective effect of forests. Experience shows that wherever there is forest, the implementation of technical measures to reduce risk of rockfall might often be dispensable or cheaper, and large deforestations (e.g. after windthrows, forest fires, clear-cuts) often show an increased incidence of rockfall events. This study focussed on how the protective effect of a forest against rockfall can be quantified on an alpine transregional scale. We therefore estimated the runout length, in terms of the angle of reach, of 700 individual rockfall trajectories from 39 release areas from Austria, Germany, Italy and Slovenia. All recorded rockfall events passed through forests which were classified either as coppice forests or, according to the CORINE classification of land cover, as mixed, coniferous or broadleaved dominated high forest stands. For each individual rockfall trajectory, we measured the forest structural parameters stem number, basal area, top height, ratio of shrub to high forest and share of coniferous trees. To quantify the protective effect of forests on rockfall, a hazard reduction factor is introduced, defined as the ratio between an expected angle of reach without forest and the back-calculated forest-influenced angles of reach. The results show that forests significantly reduce the runout length of rockfall. The highest reduction was observed for mixed high forest stands, while the lowest hazard reduction was observed for high forest stands dominated either by coniferous or broadleaved tree species. This implies that as soon as one tree species dominates, the risk reduction factor becomes lower. Coppice forests showed the lowest variability in hazard reduction. Hazard reduction due to forests increases, on average, by 7% for an increase in the stem number by 100 stems per hectare. The proposed concept allows a global view of the effectiveness of protective forests against rockfall processes and thus enable to value forest ecosystem services for future transregional assessments on a European level. Based on our results, general cost–benefit considerations of nature-based solutions against rockfall, such as protective forests as well as first-order evaluations of rockfall hazard reduction effects of silvicultural measures within the different forest types, can be supported.

Tree hollows as a resource for wildlife in remnant woodlands: spatial and temporal patterns across the northern plains of Victoria, Australia

1994 ◽  
Vol 1 (3) ◽  
pp. 222 ◽  
Author(s):  
A. F. Bennett ◽  
L. F. Lumsden ◽  
A. O. Nicholls
Keyword(s):  
Tree Species ◽  
Regional Scale ◽  
Annual Rainfall ◽  
Spatial And Temporal Variation ◽  
Public Land ◽  
Northern Plains ◽  
Individual Tree ◽  
Tree Hollows ◽  
Large Trees ◽  
The Impact

Hollows in living or dead trees are an important resource for a range of animal species in Australia. They are used for diurnal and nocturnal shelter and as breeding sites, and the availability of hollows may be a limiting factor for some populations. This study examined patterns in the distribution of tree hollows at 185 sites, each of 1.0 ha, in remnant woodlands across the northern plains, Victoria, a rural region where little remains of the natural woodland cover. Spatial and temporal variation in the abundance of tree hollows is evident at several scales including that of the individual tree, the landscape and the region. For individual trees, the number of holes increased with tree diameter, and the slope of this relationship differed between tree species. The percentage of trees that are hollow-bearing also differs between species. Large trees have a higher proportion of holes with a large entrance diameter (>10 cm) and a lower proportion of small holes (?2 cm diameter) than do small trees. At the landscape scale, hollow-bearing trees were not evenly distributed throughout remnant woodlands. Significant variables in a regression model of the abundance of hollow-bearing trees included: the number of large trees (>70 cms diameter), woodland tree species composition and mean annual rainfall. At the regional scale, the availability of hollows is influenced by the patchy distribution of remnant woodlands. Large tracts are mainly associated with public land along river systems and contrast with extensive areas of farmland where woodlands are sparse or absent. The abundance of hollows at the landscape and regional scale is strongly influenced by the impact of land management on two key processes; the loss of existing hollow-bearing trees and the recruitment of new trees. On privately managed land, generally grazed by domestic stock, large trees with hollows are often present, but the scarcity of saplings and small trees raises concern over the recruitment of future hollow-bearing trees, and indeed the long-term persistence of woodland vegetation. Conversely, most sites in large blocks of public land have ample regeneration but relatively fewer hollow-bearing trees due to the loss of larger trees from timber harvesting activities. In both situations, the abundance of trees with hollows is the consequence of management practices, and their future availability is directly amenable to management action. Some implications of the patterns of distribution of hollows for wildlife are discussed.

Tree species distribution in Andean forests: influence of regional and local factors

2011 ◽  
Vol 28 (1) ◽  
pp. 83-95 ◽  
Author(s):  
Cecilia Blundo ◽  
Lucio R. Malizia ◽  
John G. Blake ◽  
Alejandro D. Brown
Keyword(s):  
Environmental Factors ◽  
Species Composition ◽  
Species Distribution ◽  
Tree Species ◽  
Altitudinal Gradient ◽  
Local Community ◽  
Climatic Factors ◽  
Regional Scale ◽  
Tree Species Composition ◽  
Local Factors

Abstract:We identified and quantified regional and local environmental factors and spatial variation associated with tree-species composition across a 2000-m altitudinal gradient of Andean forest in north-western Argentina. A network of 47 1-ha plots was established along the altitudinal gradient within an area of about 25 000 km2; all trees ≥ 10 cm dbh were identified and measured. Constrained ordinations and variance-partitioning analyses were performed to investigate the determinants of tree-species distribution at the regional scale, across and within forest types (i.e. dry and cloud forests). We marked and measured a total of 22 240 trees belonging to 160 species. Significant environmental factors and spatial location combined accounted for 35% of total variation explained. A high proportion of variation was explained by climatic factors that were spatially structured; after removing the spatial effect, climate explained more variation in species composition across the complete gradient than did local factors. Relative importance of regional and local factors varied with geographic extent. Local factors explained more variation in tree-species composition at the within-forest scale than at the scale of the complete gradient. Our findings support the conceptual model of multi-scale controls on vegetation distribution, where local community composition and abundance result from processes at both regional and local scales.

Effect of tree species mixing on stand structural complexity

2019 ◽  
Author(s):  
Julia Juchheim ◽  
Martin Ehbrecht ◽  
Peter Schall ◽  
Christian Ammer ◽  
Dominik Seidel
Keyword(s):  
Tree Species ◽  
Laser Scanning ◽  
Three Dimensional ◽  
Structural Complexity ◽  
Goods And Services ◽  
Interspecific Differences ◽  
Dimensional Distribution ◽  
Broadleaved Tree Species ◽  
Commercially Important ◽  
The Relationship

Abstract The proportion of mixed-species forests is presently increasing since they are commonly seen as providing a higher level of many ecosystem goods and services than monospecific stands. This may be due to a more complex three-dimensional distribution pattern of plant elements, which has often been noted, but to date rarely been quantified. In the present study, we used terrestrial laser scanning data to analyze the relationship between tree species mixing and stand structural complexity in three regions of Germany. We examined 60 forest plots representing commercially important and typical species combinations for Central Europe. The results showed an increasing but saturating relationship between stand structural complexity and tree species diversity. Moreover, we found that as the proportion of broadleaved trees increased, the stand structural complexity of coniferous stands also increased. Our study provides evidence that the conversion of monospecific conifer stands into mixed forests with broadleaved tree species as well as mixing tree species with interspecific differences in physiological and morphological traits can promote the development of structurally more complex stand structures.

scholarly journals Expected Impacts of Mixing European Beech with Silver Fir on Regional Air Quality and Radiation Balance

Climate ◽  
2020 ◽  
Vol 8 (10) ◽  
pp. 105
Author(s):  
Boris Bonn ◽  
Jürgen Kreuzwieser ◽  
Ruth-Kristina Magh ◽  
Heinz Rennenberg ◽  
Dirk Schindler ◽  
...  
Keyword(s):  
Air Quality ◽  
Tree Species ◽  
Cloud Condensation Nuclei ◽  
Regional Scale ◽  
Abies Alba ◽  
European Beech ◽  
Radiation Balance ◽  
Silver Fir ◽  
Radiative Balance ◽  
Air Chemistry

The anticipated climate change during the next decades is posing crucial challenges to ecosystems. In order to decrease the vulnerability of forests, introducing tree species’ mixtures are a viable strategy, with deep-rooting native Silver fir (Abies alba) being a primary candidate for admixture into current pure stands of European beech (Fagus sylvatica) especially in mountainous areas. Such a change in forest structure also has effects on the regional scale, which, however, have been seldomly quantified. Therefore, we measured and modeled radiative balance and air chemistry impacts of admixing Silver fir to European beech stands, including changes in biogenic volatile organic compound emissions. An increased fraction of Silver fir caused a smaller albedo and a (simulated) larger evapotranspiration, leading to a dryer and warmer forest. While isoprene emission was negligible for both species, sesquiterpene and monoterpene emissions were larger for fir than for beech. From these differences, we derived that ozone concentration as well as secondary organic aerosols and cloud condensation nuclei would increase regionally. Overall, we demonstrated that even a relatively mild scenario of tree species change will alter the energy balance and air quality in a way that could potentially influence the climate on a landscape scale.

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