Effect of stand structure and aspect on the regeneration of banj oak (Quercus leucotrichophora A. Camus) forest along disturbance in Garhwal Himalaya, Uttarakhand, India

A study was conducted in an oak forest, to find out the relationship of stand structure, aspect and regeneration of species. Among all disturbance stands the density of banj oak Quercus leucotrichophora A. Camus individuals was peaked at 40–50 cm and 50–60 cm diameter at breast height (DBH) classes and low tree density was observed with the increasing DBH classes. North aspect showed higher density for most of girth classes as compared to south facing aspect. Among all the stands, low seedling density was recorded in undisturbed stand at south facing aspect as compared to the moderately and highly disturbed stands. The tree density of Q. leucotrichophora was higher in the undisturbed stand followed by moderately disturbed and highly disturbed stand. But in case of seedling density the higher density were observed at undisturbed and highly disturbed stand in both of the aspects.

Disturbance macroecology: integrating disturbance ecology and macroecology with different-age post-fire stands of a closed-cone pine forest

Macroecological studies have generally restricted their scope to relatively steady-state systems, and as a result, how biodiversity and abundance metrics are expected to scale in disturbance-dependent ecosystems is unknown. We examine macroecological patterns in a fire-dependent forest of Bishop pine (Pinus muricata). We target two different-aged stands in a stand-replacing fire regime, one a characteristically mature stand with a diverse understory, and one more recently disturbed by a stand-replacing fire (17 years prior to measurement). We compare the stands using macroecological metrics of species richness, abundance and spatial distributions that are predicted by the Maximum Entropy Theory of Ecology (METE), an information-entropy based theory that has proven highly successful in predicting macroecological metrics across a wide variety of systems and taxa. Ecological patterns in the mature stand more closely match METE predictions than do data from the recently disturbed stand. This suggests METE’s predictions are more robust in late-successional, slowly changing, or steady-state systems than those in rapid flux with respect to species composition, abundances, and organisms’ sizes. Our findings highlight the need for a macroecological theory that incorporates natural disturbance and other ecological perturbations into its predictive capabilities, because most natural systems are not in a steady state.

Quantification of time delay between damages caused by windstorms and by Ips typographus

Damages by wind and by European spruce bark beetle (I. typographusL.) were compared on the basis of the reports about the occurrence of harmful forest agents for the period 1964−1991 across former regional state forest directorates. In the given period, the quantity of salvage logging (70 million m3) was more than five times that of sanitation felling (13 million m3). Damage intensity increased over the decades. Using a cross-correlation function between the time series, an increase in the abundance ofI. typographusdue to windfall was demonstrated with a delay of 1–3 years. Wind damage was also shown to arise as a result of disturbed stand stability after sanitation felling with a stochastic delay of 1−5 years. Thus, disturbance of static stability of forest stands may be considered as one of the main harmful consequences of bark beetle outbreaks for the near future. Consequences for forest management are discussed.

Functional species traits of carabid beetles living in two riparian alder forests of the Sila plateau subject to different disturbance factors (Coleoptera: Carabidae)

We studied carabid beetle assemblages found in riparian black alder forests in the Sila plateau (Southern Apennines). These carabid assemblages are characterized by a high incidence of endemic small-sized, low dispersal, highly stenotopic (hygrophilic), and trophycally specialized species. To evaluate the influence of anthropogenic disturbance on these insects, we compared carabid assemblage of an old undisturbed forest (65-170y, wilderness landscape) with that of a younger, partly grazed stand (40-60y, cropland landscape). The carabid assemblage of the disturbed stand was characterized by a higher number of species, but showed a lower incidence of zoophagous specialists and brachypterous beetles, with many species probably coming from an adjacent cropland. However, the disturbed stand maintains almost 80% of the core species found in the older forest, which suggests that these insects are not particularly sensitive to disturbance factors represented by periodic wood harvesting and extensive cattle grazing.

Effect of disturbance on fine root biomass in the Tropical moist forest of eastern Nepal

Fine root biomass (<5 mm diameter) was estimated in 0-15 cm and 15- 30 cm soil depths of disturbed and undisturbed stands of tropical moist forest in eastern Nepal. The value of root mass was higher (4.28 t ha-1) in the undisturbed stand than the disturbed stand (2.04 t ha-1). The biomass of smaller fine roots (<2 mm diameter) was 1.51 and 3.2 t ha-1 in the disturbed and undisturbed stands respectively. Most of the fine roots were present in the surface soil layer (0-15 cm), in both the disturbed and undisturbed stands (67% in the disturbed and 64% in the undisturbed). The nitrogen stock in the fine roots was more (38.61 kg ha-1) in undisturbed stand than the disturbed stand (16.93 kg ha-1). More nitrogen was confined in the fine roots of <2 mm diameter in both undisturbed (28.8 kg ha-1) and disturbed (13.59 kg ha-1) stands. DOI: http://dx.doi.org/10.3126/njbs.v2i0.7484 Nepalese Journal of Biosciences 2 : 10-16 (2012)

Various aspects of soil and tree layer vegetation analysis in tropical dry deciduous forest of Hastinapur

Different parameters of Soil and vegetation analysis were carried out in Tropical dry deciduous forest of Hastinapur region of Uttar Pradesh. Vegetation of present study sites showed effects of various anthropogenic disturbances. The highly disturbed stand I showed low tree density while less disturbed stand III showed high tree density and good regeneration pattern. D-D curve were also drawn on the basis of the IVI of different species. Population structure of different tree species was drawn to understand the regeneration pattern. The most characteristic feature of the forest is dominance of xerophytic species and open forest canopy due to disturbances. Overgrazing and other biotic factors are making the area poor both in nutrient and top soil, which will eventually result in desertification of the Hastinapur in long run.

Dynamics of tree seedling populations in a humid subtropical forest of northeast India as related to disturbance

Recruitment and survival of four important broad-leaved tree species, viz Quercusdealbata L., Quercusgriffithii Hk., Rhododendronarboreum Sm., and Schimakhasiana Dyer., were studied over 2 years in the undisturbed, mildly disturbed and highly disturbed forest stands of a subtropical humid forest of Meghalaya, northeast India. Recruitment of S. khasiana seedlings was maximum in the highly disturbed stand, while Q. dealbata seedlings were abundant in the undisturbed and mildly disturbed stands. Seedlings of Q. dealbata, Q. griffithii, and R. arboreum were equally successful in all the stands, while S. khasiana seedlings showed better survival in the highly disturbed stand than in the mildly disturbed and undisturbed stands. Six microenvironmental factors, viz photosynthetically active radiation, relative humidity, air temperature, soil temperature, soil moisture, and thickness of litter on the forest floor, were correlated with the age-specific mortality rate of seedlings. In Q. dealbata, Q. griffithii, and S. khasiana, mortality rate was significantly affected by microenvironmental factors, while in R. arboreum mortality was not correlated with any of the microenvironmental factors. On the basis of seedling recruitment and survival pattern, it was concluded that Q. dealbata, Q. griffithii, and R. arboreum were successful in both disturbed and undisturbed forest stands, while S. khasiana seedlings showed better survival and establishment in the disturbed stands.