Evaluating relationships among tree growth rate, shade tolerance, and browse tolerance following disturbance in an eastern deciduous forest

Interspecific differences in shade tolerance among woody species are considered a primary driving force underlying forest succession. However, variation in shade tolerance may be only one of many interspecific differences that cause species turnover. For example, tree species may differ in their sensitivity to herbivory. Nonetheless, existing conceptual models of forest dynamics rarely explicitly consider the impact of herbivores. We examined whether browsing by white-tailed deer ( Odocoileus virginianus Zimmermann) alters the relationship between light availability and plant performance. We monitored growth and survival for seedlings of six woody species over 2 years within six windthrow gaps and the nearby intact forest in the presence and absence of deer. Browsing decreased seedling growth for all species except beech ( Fagus grandifolia Ehrh.). More importantly, browsing altered growth rankings among species. Increased light availability enhanced growth for three species when excluded from deer, but browsing obscured these relationships. Browsing also reduced survival for three species; however, survival rankings did not significantly differ between herbivory treatments. Our results indicated that browsing and light availability operated simultaneously to influence plant growth within these forests. Thus, existing models of forest dynamics may make inaccurate predictions of the timing and composition of species reaching the canopy, unless they can account for how plant performance varies as a result of a variety of environmental factors, including herbivory.

Download Full-text

Effects of simulated post-harvest light availability and soil compaction on deciduous forest herbs

Canadian Journal of Forest Research ◽

10.1139/x02-099 ◽

2002 ◽

Vol 32 (10) ◽

pp. 1753-1762 ◽

Cited By ~ 29

Author(s):

Christine J Small ◽

Brian C McCarthy

Keyword(s):

Soil Compaction ◽

Deciduous Forest ◽

Light Availability ◽

Natural Disturbance ◽

Deciduous Forests ◽

Herbaceous Plant ◽

Eastern Deciduous Forest ◽

Forest Herbs ◽

Successional Species ◽

Eastern Deciduous Forests

To better understand the response of eastern deciduous forest herbs to microenvironmental changes associated with logging, the effects of experimental light and soil compaction treatments were examined in six herbaceous plant species characteristic of varying successional stages. We found severe growth reductions and increased mortality of Osmorhiza claytonii (Michx.) C.B. Clarke, a shade-tolerant forest perennial, when grown in full sun and greater soil compaction. Deeply shaded conditions, similar to those beneath regenerating forests, resulted in reduced growth of early successional species such as Galium aparine L., and Eupatorium rugosum Houtt. Growth of other species such as Geum canadense Jacq., and Elymus hystrix L. appeared to increase in the patchy, intermediate light treatment mimicking mature eastern deciduous forests. Soil compaction caused severe reductions in height and biomass of Eupatorium rugosum and O. claytonii, early- and late-successional species, respectively. While harvested stands experience relatively uniform light environments, canopy gaps and sunflecks in mature eastern deciduous forests create heterogeneous light environments often correlated with recruitment, growth, and diversity of understory herbs. Therefore, management approaches that minimize alteration of forest environments and mimic natural disturbance patterns may be important to the maintenance and regeneration of forest herbs.

Download Full-text

Leaf weight per area and leaf size of 85 Estonian woody species in relation to shade tolerance and light availability

Forest Ecology and Management ◽

10.1016/0378-1127(94)90070-1 ◽

1994 ◽

Vol 70 (1-3) ◽

pp. 1-10 ◽

Cited By ~ 96

Author(s):

Ülo Niinemets ◽

Kalevi Kull

Keyword(s):

Shade Tolerance ◽

Light Availability ◽

Woody Species ◽

Leaf Size ◽

Leaf Weight

Download Full-text

Distribution of black spruce versus eastern larch along peatland gradients: relationship to relative stature, growth rate, and shade tolerance

Canadian Journal of Botany ◽

10.1139/b96-182 ◽

1996 ◽

Vol 74 (9) ◽

pp. 1514-1532 ◽

Cited By ~ 24

Author(s):

Timothy G. Montague ◽

Thomas J. Givnish

Keyword(s):

Shade Tolerance ◽

Black Spruce ◽

Woody Species ◽

Height Growth ◽

Larix Laricina ◽

Costs And Benefits ◽

Natural Gradient ◽

Interspecific Differences ◽

And Performance ◽

Historic Change

The relative abundance and performance of black spruce (Picea mariana) and eastern larch (Larix laricina) were quantified along fertility gradients in two peatlands in northern Wisconsin. We hypothesized that (i) the distribution of these two dominants should correspond to the portions of the gradient where each has an advantage in stature and (or) rate of height growth relative to its principal competitor; that (ii) larch should have a higher rate of height growth on wetter, more minerotrophic sites, based on the costs and benefits of its deciduous habit; and that (iii) spruce should be more shade tolerant and increase in abundance during succession. Our findings largely support these hypotheses, and (at the hydrologically stable site) provide the first circumstantial evidence for the competitive sorting of woody species along a natural gradient. The incongruity of interspecific differences in height and growth at one of the two sites is evidence for an historic change in the environment there, involving a shift in hydrology around 1925. Keywords: competitive sorting, deciduousness, evergreenness, Larix, Picea, Thuja.

Download Full-text

Impacts of separate rejection water treatment on the overall plant performance

Water Science & Technology ◽

10.2166/wst.2003.0240 ◽

2003 ◽

Vol 48 (4) ◽

pp. 139-146 ◽

Cited By ~ 17

Author(s):

B. Wett ◽

J. Alex

Keyword(s):

Water Treatment ◽

Treatment Plant ◽

Operating Experience ◽

Plant Performance ◽

High Tech ◽

State Variables ◽

Total N ◽

Unit Process ◽

Innovative Tool ◽

The Impact

A separate rejection water treatment appears as a high-tech unit process which might be recommendable only for specific cases of an upgrading of an existing wastewater treatment plant. It is not the issue of this paper to consider a specific separate treatment process itself but to investigate the influence of such a process on the overall plant performance. A plant-wide model has been applied as an innovative tool to evaluate effects of the implemented sidestream strategy on the mainstream treatment. The model has been developed in the SIMBA environment and combines acknowledged mathematical descriptions of the activated sludge process (ASM1) and the anaerobic mesophilic digestion (Siegrist model). The model's calibration and validation was based on data from 5 years of operating experience of a full-scale rejection water treatment. The impact on the total N-elimination efficiency is demonstrated by detailed nitrogen mass flow schemes including the interactions between the wastewater and the sludge lane. Additionally limiting conditions due to dynamic N-return loads are displayed by the model's state variables.

Download Full-text

Beavers, Bugs and Chemistry: A Mammalian Herbivore Changes Chemistry Composition and Arthropod Communities in Foundation Tree Species

Forests ◽

10.3390/f12070877 ◽

2021 ◽

Vol 12 (7) ◽

pp. 877

Author(s):

Rachel M. Durben ◽

Faith M. Walker ◽

Liza Holeski ◽

Arthur R. Keith ◽

Zsuzsi Kovacs ◽

...

Keyword(s):

Tree Species ◽

Castor Canadensis ◽

Habitat Type ◽

Food Preferences ◽

Woody Species ◽

Juvenile Growth ◽

Arthropod Community ◽

Riparian Ecosystems ◽

Arthropod Communities ◽

The Impact

The North American beaver (Castor canadensis Kuhl) and cottonwoods (Populus spp.) are foundation species, the interactions of which define a much larger community and affect a threatened riparian habitat type. Few studies have tested the effect of these interactions on plant chemistry and a diverse arthropod community. We experimentally examined the impact of beaver foraging on riparian communities by first investigating beaver food preferences for one cottonwood species, Fremont cottonwood (P. fremontii S. Watson), compared to other locally available woody species. We next examined the impact of beaver foraging on twig chemistry and arthropod communities in paired samples of felled and unfelled cottonwood species in northern Arizona (P. fremontii) and southwestern Colorado (narrowleaf cottonwood, P. angustifolia James, and Eastern cottonwood, P. deltoides W. Bartram ex Marshall). Four major patterns emerged: (1) In a cafeteria experiment, beavers chose P. fremontii six times more often than other woody native and exotic species. (2) With two cottonwood species, we found that the nitrogen and salicortin concentrations were up to 45% greater and lignin concentration 14% lower in the juvenile resprout growth of felled trees than the juvenile growth on unfelled trees (six of seven analyses were significant for P. fremontii and four of six were significant for P. angustifolia). (3) With two cottonwood species, arthropod community composition on juvenile branches differed significantly between felled and unfelled trees, with up to 38% greater species richness, 114% greater relative abundance and 1282% greater species diversity on felled trees (six of seven analyses with P. fremontii and four of six analyses with P. angustifolia were significant). The above findings indicate that the highest arthropod diversity is achieved in the heterogenous stands of mixed felled and unfelled trees than in stands of cottonwoods, where beavers are not present. These results also indicate that beaver herbivory changes the chemical composition in 10 out of 13 chemical traits in the juvenile growth of two of the three cottonwood species to potentially allow better defense against future beaver herbivory. (4) With P. deltoides, only one of five analyses in chemistry was significant, and none of the four arthropod community analyses were significant, suggesting that this species and its arthropod community responds differently to beaver. Potential reasons for these differences are unknown. Overall, our findings suggest that in addition to their impact on riparian vegetation, other mammals, birds, and aquatic organisms, beavers also may define the arthropod communities of two of three foundation tree species in these riparian ecosystems.

Download Full-text