The Role of Fallen Logs in the Regeneration of Tree Species in Tasmanian Mixed Forest

1999 ◽  
Vol 47 (5) ◽  
pp. 745 ◽  
Author(s):  
J. B. Kirkpatrick ◽  
H. J. A. McKenny
Keyword(s):  
Bulk Density ◽  
Tree Species ◽  
Substrate Surface ◽  
Mixed Forest ◽  
Canopy Cover ◽  
Root Competition ◽  
Tree Seedlings ◽  
Establishment Success ◽  
Moss Cover ◽  
Litter Cover

This study was designed to determine whether fallen logs were a more favourable habitat for tree species establishment than soil in moist eucalypt forest in Tasmania, whether establishment success on logs varied between two forests in contrasting environments, and whether surface and substrate qualities and light conditions were associated with establishment success. Data on tree and shrub species densities and heights by species, moss cover, litter cover, Blechnum wattsii cover, canopy cover, bulk density of the substrate, and substrate surface pH, nitrogen content and phosphorus content were obtained from paired soil and log quadrats. Tree seedlings were found to be significantly more abundant on fallen logs than on adjacent ground at both sites, with the differences being greater at the moister Tahune site than at Mount Field. At Tahune, logs significantly differed from adjacent soil in canopy cover, litter cover, moss cover Blechnum wattsii cover, pH and slope. At Mount Field, there were significant differences between logs and soil in litter cover, moss cover, pH, bulk density and nitrogen. Litter cover may be critical in explaining the superior establishment of trees on logs rather than soil in Tasmanian mixed forest, although the possible impacts of variations in bioturbation and root competition require further research.

Factors influencing early vegetation establishment following soil scarification in a mixed forest in northern Japan

2005 ◽  
Vol 35 (1) ◽  
pp. 175-188 ◽  
Author(s):  
Toshiya Yoshida ◽  
Yoko Iga ◽  
Megumi Ozawa ◽  
Mahoko Noguchi ◽  
Hideaki Shibata
Keyword(s):  
Species Diversity ◽  
Plant Species ◽  
Tree Species ◽  
Mixed Forest ◽  
Canopy Cover ◽  
Total Density ◽  
Dwarf Bamboo ◽  
Negative Effects ◽  
Tall Tree ◽  
Northern Japan

Scarification is widely conducted in northern Japan to remove understory dwarf bamboo species in degraded forests for replacement with tree species. To explore ways to enhance species diversity and restoration of mixed forest at the treated site, we clarified the mechanisms that lead to compositional heterogeneity of plant species. We evaluated the relative importance of environmental factors (scarification properties, soil properties, light conditions, litter cover, and presence of canopy trees) for the demography of tall tree species (emergence, mortality, and growth) and whole vegetation structure (species diversity and composition) over the two growing seasons immediately following scarification. Of tall tree species, Betula spp. were dominant (60% in total density), followed by Abies sachalinensis (Fr. Schm.) Masters, Acer mono Maxim., and Phellodendron amurense Rupr. Light intensity was an important factor, having mostly negative effects on the demography of these species. Soil factors (e.g., nitrogen content, moisture) affected the demography mainly of shade-intolerant or hygrophilous species. In general, extreme environmental conditions led to the dominance of grasses, forbs, and lianas rather than tall trees. Maintenance of canopy cover, which limits light and supplies seeds as well as litter, proved to be most important in promoting plant species diversification on the scarification site.

Above- and below-ground competition in high and low irradiance: tree seedling responses to a competing liana Byttneria grandifolia

2008 ◽  
Vol 24 (05) ◽  
pp. 517-524 ◽  
Author(s):  
Ya-Jun Chen ◽  
Frans Bongers ◽  
Kun-Fang Cao ◽  
Zhi-quan Cai
Keyword(s):  
Leaf Area ◽  
Tree Species ◽  
Morphological Traits ◽  
Root Competition ◽  
Tree Seedlings ◽  
Tree Seedling ◽  
Relative Growth Rates ◽  
Shoot Competition ◽  
Shade Tolerant Species ◽  
Below Ground

Abstract:In tropical forests, trees compete not only with other trees, but also with lianas, which may limit tree growth and regeneration. Liana effects may depend on the availability of above- and below-ground resources and differ between tree species. We conducted a shade house experiment to test the effect of light (4% and 35% full sun, using neutral-density screen) on the competitive interactions between seedlings of one liana (Byttneria grandifolia) and three tree species (two shade-tolerant trees,Litsea dilleniifoliaandPometia tomentosa, and one light-demanding tree,Bauhinia variegata) and to evaluate the contribution of both above- and below-ground competition. Trees were grown in four competition treatments with the liana: no competition, root competition, shoot competition and root and shoot competition. Light strongly affected leaf photosynthetic capacity (light-saturated photosynthetic rate,Pn), growth and most morphological traits of the tree species. Liana-induced competition resulted in reducedPn, total leaf areas and relative growth rates (RGR) of the three tree species. The relative importance of above- and below-ground competition differed between the two light levels. In low light, RGR of the three tree species was reduced more strongly by shoot competition (23.1–28.7% reduction) than by root competition (5.3–26.4%). In high light, in contrast, root competition rather than shoot competition greatly reduced RGR. Liana competition affected most morphological traits (except for specific leaf area and leaf area ratio ofLitseaandPometia), and differentially altered patterns of biomass allocation in the tree seedlings. These findings suggest that competition from liana seedlings can greatly suppress growth in tree seedlings of both light-demanding and shade-tolerant species and those effects differ with competition type (below- and above-ground) and with irradiance.

scholarly journals Fire suppression and seed dispersal play critical roles in the establishment of tropical forest tree species in southeastern Africa

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tomohiro Fujita
Keyword(s):  
Seed Dispersal ◽  
Tree Species ◽  
Seedling Survival ◽  
Fire Suppression ◽  
Forest Tree ◽  
Tree Seedlings ◽  
Seedling Mortality ◽  
Forest Tree Species ◽  
Seed Deposition ◽  
Syzygium Guineense

AbstractThis study examined the mechanisms of facilitation and importance of seed dispersal during establishment of forest tree species in an Afrotropical woodland. Seedling survival of Syzygium guineense ssp. afromontanum was monitored for 2.5 years at four different microsites in savannah woodland in Malawi (southeastern Africa) under Ficus natalensis (a potential nurse plant), Brachystegia floribunda (a woodland tree), Uapaca kirkiana (a woodland tree), and at a treeless site. The number of naturally established forest tree seedlings in the woodland was also counted. Additionally, S. guineense ssp. afromontanum seed deposition was monitored at the four microsites. Insect damage (9% of the total cause of mortality) and trampling by ungulates (1%) had limited impact on seedling survival in this area. Fire (43%) was found to be the most important cause of seedling mortality and fire induced mortality was especially high under U. kirkiana (74%) and at treeless site (51%). The rate was comparatively low under F. natalensis (4%) and B. floribunda (23%), where fire is thought to be inhibited due to the lack of light-demanding C4 grasses. Consequently, seedling survival under F. natalensis and B. floribunda was higher compared with the other two microsites. The seedling survival rate was similar under F. natalensis (57%) and B. floribunda (59%). However, only a few S. guineense ssp. afromontanum seedlings naturally established under B. floribunda (25/285) whereas many seedlings established under F. natalensis (146/285). These findings indicate that the facilitative mechanism of fire suppression is not the only factor affecting establishment. The seed deposition investigation revealed that most of the seeds (85%) were deposited under F. natalensis. As such, these findings suggest that in addition to fire suppression, dispersal limitations also play a role in forest-savannah dynamics in this region, especially at the community level.

scholarly journals Does Mixing Tree Species Affect Water Storage Capacity of the Forest Floor? Laboratory Test of Pine-Oak and Fir-Beech Litter Layers

Forests ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1674
Author(s):  
Anna Ilek ◽  
Małgorzata Szostek ◽  
Anna Mikołajczyk ◽  
Marta Rajtar
Keyword(s):  
Physical Properties ◽  
Bulk Density ◽  
Tree Species ◽  
Forest Floor ◽  
Storage Capacity ◽  
Water Storage ◽  
Pine Needles ◽  
Litter Layer ◽  
Water Storage Capacity ◽  
Organic Debris

During the last decade, tree species mixing has been widely supported as a silvicultural approach to reduce drought stress. However, little is known on the influence of tree species mixing on physical properties and the water storage capacity of forest soils (including the forest floor). Thus, the study aimed to analyze the effect of mixing pine needles and oak leaves and mixing fir needles and beech leaves on hydro-physical properties of the litter layer during laboratory tests. We used fir-beech and pine-oak litter containing various shares of conifer needles (i.e., 0, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90 and 100%) to determine the influence of the needle admixture on bulk density, total porosity, macroporosity, water storage capacity, the amount of water stored in pores between organic debris and the degree of saturation of mixed litter compared to broadleaf litter (oak or beech). We found that the admixture of fir needles increased the bulk density of litter from 7.9% with a 5% share of needles to 55.5% with a 50% share (compared to pure beech litter), while the share of pine needles < 40% caused a decrease in bulk density by an average of 3.0–11.0% (compared to pure oak litter). Pine needles decreased the water storage capacity of litter by about 13–14% with the share of needles up to 10% and on average by 28% with the 40 and 50% shares of pine needles in the litter layer. Both conifer admixtures reduced the amount of water stored in the pores between organic debris (pine needles more than fir needles).

scholarly journals Factors Influencing the Natural Forest Regeneration at Khadimnagar National Park, Bangladesh

2021 ◽  
Vol 11 (1) ◽  
pp. 73-83
Author(s):  
MAHEDI HASAN LIMON ◽  
SAIDA HOSSAIN ARA ◽  
MOHAMMAD GOLAM KIBRIA
Keyword(s):  
Species Richness ◽  
Bulk Density ◽  
Total Variation ◽  
Soil Ph ◽  
Tree Species ◽  
Natural Regeneration ◽  
National Park ◽  
Canopy Openness ◽  
Site Factors ◽  
Tree Species Richness

Natural regeneration is an indicator of a healthy forest, hence, understanding the influence of site factors on natural regeneration is a significant concern for ecologists. This work aimed to assess the impact of site factors on natural tree regeneration at Khadimnagar National Park (KNP). Biotic factors (tree density, tree species richness, and basal area), physical factors (elevation, canopy openness), and soil properties (bulk density, moisture content, soil pH, organic matter, sand, silt, and clay) data were investigated from 71 sample plots to examine their effects on natural regeneration density and richness in KNP. Stepwise multiple linear regression analysis was done to predict both regeneration density and regeneration richness. The results showed that soil pH (p<0.001), canopy openness (p<0.001), tree species richness (p<0.01), and bulk density (p<0.01) had a significant effect on regeneration density, explaining 42% of the total variation. Regeneration richness was driven by four factors: tree species richness (p<0.01), soil pH (p<0.001), elevation (p<0.01), and canopy openness (p<0.01) with a model that explained 60% of the total variation. This study observed that soil pH, tree species richness, and canopy openness are the main controlling factors that influenced both the density and richness of regenerating species in KNP. Therefore, these findings have implications for natural resource management, especially in selecting suitable silvicultural systems in a tropical forest under protected area management where enhanced tree cover and conservation of biodiversity are needed.

Carbon exchange in a hemiboreal mixed forest in relation to tree species composition

2019 ◽  
Vol 275 ◽  
pp. 11-23 ◽  
Author(s):  
Alisa Krasnova ◽  
Mai Kukumägi ◽  
Ülo Mander ◽  
Raili Torga ◽  
Dmitrii Krasnov ◽  
...  
Keyword(s):  
Species Composition ◽  
Tree Species ◽  
Mixed Forest ◽  
Carbon Exchange ◽  
Tree Species Composition

Estimating canopy fuel characteristics for predicting crown fire potential in common forest types of the Atlantic Coastal Plain, USA

2018 ◽  
Vol 27 (11) ◽  
pp. 742 ◽  
Author(s):  
Anne G. Andreu ◽  
John I. Blake ◽  
Stanley J. Zarnoch
Keyword(s):  
Bulk Density ◽  
Coastal Plain ◽  
Canopy Cover ◽  
Atlantic Coastal Plain ◽  
Theoretic Approach ◽  
Crown Fire ◽  
Prescribed Burns ◽  
Stand Height ◽  
Atlantic Coastal ◽  
Canopy Bulk Density

We computed four stand-level canopy stratum variables important for crown fire modelling – canopy cover, stand height, canopy base height and canopy bulk density – from forest inventory data. We modelled the relationship between the canopy variables and a set of common inventory parameters – site index, stem density, basal area, stand age or stand height – and number of prescribed burns. We used a logistic model to estimate canopy cover, a linear model to estimate the other canopy variables, and the information theoretic approach for model selection. Coefficients of determination across five forest groups were 0.72–0.91 for stand height, 0.36–0.83 for canopy base height, 0.39–0.80 for canopy cover, and 0.63–0.78 for canopy bulk density. We assessed crown fire potential (1) for several sets of environmental conditions in all seasons, and (2) with increasing age, density and number of prescribed burns using our modelled canopy bulk density and canopy base height variables and local weather data to populate the Crown Fire Initiation and Spread model. Results indicated that passive crown fire is possible in any season in Atlantic coastal plain pine stands with heavy surface fuel loads and active crown fire is most probable in infrequently burned, dense stands at low fuel moistures.

scholarly journals The effect of flooding on the exchange of the volatile C<sub>2</sub>-compounds ethanol, acetaldehyde and acetic acid between leaves of Amazonian floodplain tree species and the atmosphere

2008 ◽  
Vol 5 (4) ◽  
pp. 1085-1100 ◽  
Author(s):  
S. Rottenberger ◽  
B. Kleiss ◽  
U. Kuhn ◽  
A. Wolf ◽  
M. T. F. Piedade ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Ethanol Production ◽  
Tree Species ◽  
Proton Transfer Reaction ◽  
Early Morning ◽  
Enzymatic Oxidation ◽  
Tree Seedlings ◽  
Emission Rates ◽  
Transpiration Stream ◽  
Species Specific

Abstract. The effect of root inundation on the leaf emissions of ethanol, acetaldehyde and acetic acid in relation to assimilation and transpiration was investigated with 2–3 years old tree seedlings of four Amazonian floodplain species by applying dynamic cuvette systems under greenhouse conditions. Emissions were monitored over a period of several days of inundation using a combination of Proton Transfer Reaction Mass Spectrometry (PTR-MS) and conventional techniques (HPLC, ion chromatography). Under non-flooded conditions, none of the species exhibited measurable emissions of any of the compounds, but rather low deposition of acetaldehyde and acetic acid was observed instead. Tree species specific variations in deposition velocities were largely due to variations in stomatal conductance. Flooding of the roots resulted in leaf emissions of ethanol and acetaldehyde by all species, while emissions of acetic acid were only observed from the species exhibiting the highest ethanol and acetaldehyde emission rates. All three compounds showed a similar diurnal emission profile, each displaying an emission burst in the morning, followed by a decline in the evening. This concurrent behavior supports the conclusion, that all three compounds emitted by the leaves are derived from ethanol produced in the roots by alcoholic fermentation, transported to the leaves with the transpiration stream and finally partly converted to acetaldehyde and acetic acid by enzymatic processes. Co-emissions and peaking in the early morning suggest that root ethanol, after transportation with the transpiration stream to the leaves and enzymatic oxidation to acetaldehyde and acetate, is the metabolic precursor for all compounds emitted, though we can not totally exclude other production pathways. Emission rates substantially varied among tree species, with maxima differing by up to two orders of magnitude (25–1700 nmol m−2 min−1 for ethanol and 5–500 nmol m−2 min−1 for acetaldehyde). Acetic acid emissions reached 12 nmol m−2 min−1. The observed differences in emission rates between the tree species are discussed with respect to their root adaptive strategies to tolerate long term flooding, providing an indirect line of evidence that the root ethanol production is a major factor determining the foliar emissions. Species which develop morphological root structures allowing for enhanced root aeration produced less ethanol and showed much lower emissions compared to species which lack gas transporting systems, and respond to flooding with substantially enhanced fermentation rates and a non-trivial loss of carbon to the atmosphere. The pronounced differences in the relative emissions of ethanol to acetaldehyde and acetic acid between the tree species indicate that not only the ethanol production in the roots but also the metabolic conversion in the leaf is an important factor determining the release of these compounds to the atmosphere.

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