the present study aimed to assess pure planted species (i.e., alnus subcordata l., poplus deltoids l., taxadium distichum l. rich) and a mixed natural forest (i.e., dominated by quercus castaneifolia c. a. mey. - carpinus betulus l. - parrotia persica c. a. meyer) on basis of some soil quality indices in mazandaran province, northern iran. sixteen samples per stand were taken from the top 10 cm...

in order to study the qualitative, quantitative characteristics of a pure common populus alba stand in polkalleh & a mixed stand of populus alba & populus nigra in karchegan, two 30-year-old stands were selected with a plantation interval ( spacing) of 2.5 × 1.5 m in each of which 30 pcs of 2 are samples were randomly selected. in each sample pc all the trees diameters were measured using a dia...

A regeneration survey in southern New England in three different cover types indicated that most of the seedhngs present were less than 19.7 in. in height. Although red oak was a principal component of he overstory, it represented a small proportion of regeneration. Black b•rch and red maple were common regeneration components. There was a general relationship between overstory density and the ...

Mixed cropping is practised widely in developing countries and is gaining increasing interest for sustainable agriculture in developed countries. Plants in intercrops grow differently from plants in single crops, due to interspecific plant interactions, but adaptive plant morphological responses to competition in mixed stands have not been studied in detail. Here the maize (Zea mays) response t...

For \natural enough" systems of ordinal notation we show that times iterated local reeection schema over a suuciently strong arithmetic T proves the same 0 1-sentences as ! times iterated consistency. A corollary is that the two hierarchies catch up modulo relative interpretability exactly at-numbers. We also derive the following more general \mixed" formulas estimating the consistency strength...

hybridization is normally prevented by different flowering times in the two species, but under certain climatic/weather conditions hybridization may occur (Dorman and Barber 1956), and natural hybrids of shortleaf pine and loblolly pine have been reported (Zobel 1953, Hare and Switzer 1969, Edwards-Burke et al. 1997 and Stewart et al. 2010). The questions are where, when, and why do they hybrid...

Intensive pine (Pinus spp.) management is a primary land use in the southeastern United States. In eastern North Carolina, intensively managed pine stands often occur on land previously ditched and drained. Because modification of natural vegetation and water sources are known to affect dipteran community structure, we studied effects of intensive pine management on abundance and diversity of d...