Unmanaged Beech Forest Research Articles

Do population indicators work? Investigating correlated responses of bird populations in relation to predator management

Using population indicators to evaluate conservation achievements is widely practised, yet seldom empirically tested. If populations are consistently correlated in response to a shared ecological driver, the indicator species approach can be used as a cost-effective, ecologically-based shortcut to measuring the effects of conservation management. Long-term monitoring of forest bird populations associated with mammalian pest control programmes in New Zealand provides a useful framework for testing the population indicator species concept. We evaluated population trends in 21 bird species vulnerable to predation by introduced mammals (primarily mustelids and rodents) at managed and unmanaged beech (Nothofagus) forest sites. Correlated population trends between species pairs were detected at individual sites. However, neither positive nor negative correlations in species trends could be predicted by life history traits and predator management did not produce consistent, correlated population trends among sites. Our results do not support the use of a population indicator approach to management and reporting for forest birds in New Zealand. Relationships between purported indicator taxa and other species need to be understood for various management scenarios before population indicators can be confidently applied to measuring conservation achievement.

Swedish beech forests and the storm gap theory

The storm gap theory of forest dynamics was developed by Sernander largely as a result of his investigations of the Norway spruce Picea abies forests of Fibyurskog and Granskär following the great storms of 1931 and 1932.This theory is reviewed in the light of subsequent investigations and its relevance to forests of common beech, Fagus sylvatica, which Watt had also investigated in southern England; developing his theory of pattern and process in the plant community as a result. Ancient unmanaged Swedish beech forests are extremely important as they enable us to ascertain how such forests develop in a state of nature. They are often important in terms of biodiversity and the veteran trees they contain are especially valuable in the conservation of rare epiphytic lichens and bryophytes. The history of Fagus sylvatica and variations in its extent in Swedish forests during the Holocene is illustrated by a review of articles concerning a number of important forest areas.

Interventi colturali e necromassa legnosa al suolo: il caso delle faggete Casentinesi

Abstract: This paper shows the first results about quantity and quality of dead wood on the ground in beech forests of Foreste Casentinesi, Monte Falterona and Campigna National Park. The presence of dead wood depends on several factors such as forest productivity, natural disturbances and human activities. Data from some mature managed beech stands have been collected and compared with those from unmanaged beech forest (Sasso Fratino full-protected Reserve). Results do not show significant differences between managed and unmanaged forests. The dead wood varies between 5 and 8 Mg ha-1 (in terms of total dry weight) mostly composed by fine woody debris.

Species diversity and species composition of epiphytic bryophytes and lichens – a comparison of managed and unmanaged beech forests in NE Germany

AbstractThe impact of forest management on the species diversity and species composition of epiphytic bryophytes and lichens in beech forests (Fagus sylvatica) of NE Germany was analysed. The investigations were carried out in one unmanaged and in one managed forest, with 45 sample plots of 400 m2each. In the sample plots, the presence of the epiphytes on 2–4 randomly chosen trees (100 trees per forest) and seven environmental variables were recorded. The total number of species and the mean lichen density per mantle area was higher in the unmanaged forest than in the managed forest. Regression analyses and DCA revealed the diameter at breast height (dbh) as the most important factor affecting the species diversity and species composition in both forest types. The dbh was positively correlated with the number of growth anomalies and with the bark roughness of the phorophytes and thus a good indicator for the habitat quality. Moreover, the light conditions had a significant impact on the species composition in both forests types and on the species diversity in the managed forest. In particular, epiphytes demanding shady conditions and a consistent humidity may suffer from the abrupt exposition to radiation and the lower humidity after logging. Species typical for the unmanaged forest and most rare species must be considered as stenoecious as they demand the shady and humid conditions of the forest interior and grow on old, large trees. With the aim of sustaining the diversity of epiphytic bryophytes and lichens, forest management should ensure the continuous occurrence of big trees above the target diameter. In addition, a single tree selection felling method should be applied to minimise strong changes in the microclimate. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Spatial and temporal variations in soil respiration in relation to stand structure and soil parameters in an unmanaged beech forest

Soil CO2 efflux (soil respiration) plays a crucial role in the global carbon cycle and efflux rates may be strongly altered by climate change. We investigated the spatial patterns of soil respiration rates in 144 measurement locations in a 0.5-ha plot and the temporal patterns along a 300-m transect in the 0.5-ha plot. Measurements were made in an unmanaged, highly heterogeneous beech forest during 2000 and 2001. We investigated the effects of soil, roots and forest stand structure on soil respiration, and we also assessed the stability of these spatial patterns over time. Soil temperature alone explained between 68 and 95% of the temporal variation in soil respiration; however, pronounced spatial scatter of respiration rates was not explained by soil temperature. The observed spatial patterns stayed remarkably stable throughout the growing season and over 2 years. The most important structural parameter of the stand was the mean diameter at breast height of trees within a distance of 4 m of the measurement locations (m-dbh4), which explained 10-19% of the variation in soil respiration throughout the growing season. Among the soil chemical parameters, carbon content (bulk as well as dissolved) and magnesium content explained 62% of the spatial variation in soil respiration. The final best model combining soil, root and stand structural parameters (fine root biomass, soil carbon content, m-dbh4 and soil water content) explained 79% of the variation in soil respiration, illustrating the importance of both biotic and abiotic factors.

Changes in the concentrations of major, minor and rare-earth elements during leaf senescence and decomposition in a Fagus sylvatica forest

The principal fate during litter decomposition and mineralization is rather well established only for a limited number of elements, mainly essential plant nutrients and a few potentially very toxic metals. Elements which occupy the majority of the positions in the periodical system seems almost unknown in this context. The objectives were, therefore to assess differences in the behavior of 58 mineral elements during the course of beech leaf senescence and decomposition in a unmanaged Swedish beech forest growing on a podzolized soil. It is assumed that chemical properties of the elements and their ions (atomic weight, electronegativity, ionic charge and radius), accumulation and retention by fungi, contributions from atmospheric deposition, and relative plant uptake are of importance to their degree of retention and enrichment in the decomposition products. Elements considered were Ag (silver), Al (aluminium), As (arsenic), B (boron), Ba (barium), Be (beryllium), Bi (bismuth), Ca (calcium), Cd (cadmium), Ce (cerium), Co (cobalt), Cr (chromium), Cs (caesium), Cu (copper), Dy (dysprosium), Er (erbium), Eu (europium), Fe (iron), Ga (gallium), Gd (gadolinium), Ge (germanium), Hf (hafnium), Hg (mercury), Ho (holmium), In (indium), K (potassium), La (lanthanum), Li (lithium), Lu (lutetium), Mg (magnesium), Mn (manganese), Mo (molybdenum), Na (sodium), Nb (niobium), Nd (neodymium), Ni (nickel), P (phosphorus), Pb (lead), Pr (praseodymium), Rb (rubidium), S (sulfur), Sb (antimony), Sc (scandium), Se (selenium), Sm (samarium), Sn (tin), Sr (strontium), Tb (terbium), Th (thorium), Ti (titanium), Tl (thallium), Tm (thulium), U (uranium), V (vanadium), W (tungsten), Y (yttrium), Yb (ytterbium), Zn (zinc), and Zr (zirconium). The concentrations of most elements increased on a dry mass basis during senescence and decomposition with rather few elements showing a decrease. The ash contents of the dry mass did not vary much among the materials. Particularly great increases on dry mass (up to 35 times in the purely organic part of the O horizon compared to green leaves in July) were measured in the rare earth metals (Y, La, and the lanthanides) as well as in Al (21), Bi (26), In (35), Th (46) and Sn (41 times). Several oxoionic elements (U, V, As, Ge, and Sb) had also high concentration ratios. Concentration decreases or no concentration changes on dry mass from green leaves to the O horizon were measured in Ba, Ca, K, Mg, Na, Rb, and Sr. Elements originating from the leaves themselves and, not the least, atmospheric deposition, were major sources of most less common and rare elements in the O horizon of this unmanaged beech forest. The degree of retention and accumulation rate was partly controlled by chemical properties of the ions, principally atomic weight, but electronegativity was also of some positive importance to the retention. Transfer by fungi to the O horizon could be of some importance to a few, but not to most of the elements studied.

Large carbon uptake by an unmanaged 250-year-old deciduous forest in Central Germany

Unmanaged forests at a late stage of successional development are considered to be insignificant as carbon sinks, since in theory, assimilation is thought to be balanced by respiration. However, little experimental evidence for this hypothesis exists so far for forests at the ecosystem level. Therefore, we performed continuous eddy covariance measurements of carbon dioxide over an unmanaged beech forest in the Hainich National Park in Central Germany as part of the EU project CARBOEUROFLUX. This forest shows typical characteristics of an ‘advanced’ forest with large dead wood pools, a diverse stand structure and a wide tree age class distribution, up to 250 years. This forest was a large carbon sink over 2 years, with 494 g C m −2 per year in 2000 and 490 g C m −2 per year in 2001. Daytime summer fluxes were strongly controlled by photosynthetic photon flux density ( R 2=0.7–0.9), with minor effects of the ratio of diffuse to total downward radiation or the vapor pressure deficit. Nighttime CO 2 fluxes were mainly controlled by soil temperature ( R 2=0.8) and soil moisture. In addition, high nighttime CO 2 fluxes (4–6 μmol m −2 s −1) were found directly before and during bud break in spring as well as just after leaf fall of both years (2000 and 2001), reflecting stand physiology corresponding to phenological changes, independent of soil temperature. Additional wind profile measurements at five heights within the canopy revealed a decoupling of above and below canopy air flow under conditions of low friction velocity ( u *<0.4 m s −1), probably indicating down slope drainage. In conclusion, unmanaged forests at a comparatively late stage of successional development can still act as significant carbon sinks with large implications for forest management practice and negotiations about biological sinks within the Kyoto Protocol.

Influence of ground cover on earthworm communities in an unmanaged beech forest: linear gradient studies

Micro-scale changes in earthworm communities and ground cover types were studied along five transect lines in an unmanaged beech forest (Fontainebleau forest, France). Spatial patterns were interpreted in the light of interactions between earthworm species and forest architecture, ground vegetation and quantity as well as quality of litter. The anecic Lumbricus terrestris was associated with patches of the grass Melica uniflora, with poor litter cover, while most epigeic species were favoured by accumulation of litter in the absence of grass vegetation. The endogeic Aporrectodea caliginosa avoided, at least in summer time, 4-year-old gaps opened by wind storms. Under the shade of beeches, the evergreen spiny shrub Ruscus aculeatus, and in opened areas the giant herb, Phytolacca decandra, seemed repellent to most earthworm species.