Undergrowth

About: Undergrowth is a research topic. Over the lifetime, 795 publications have been published within this topic receiving 11911 citations. The topic is also known as: understorey & underbrush.

The Successional Role of Southern White Cedar, Chamaecyparis Thyoides, in Southeastern North Carolina

Abstract: A community in which the southern white cedar, Clhaiaecyparis tlyo ides (L.) BSP., is dominant occurs on peat soils of the Atlantic coastal plain. Such f orests are neither common nor extensive in view of the enormous areas of peat land in this region. The most complete study of southern white cedar is that by Korstian and Brush ('31). This study, together with those of previous investigators, supplied ecological information such as site characteristics, the aspect of the community, associated tree species, and some features regarding reproduction. The site occupied by the southern white cedar community is consistently peat bog underlain by sand (Korstian, '24; Korstian and Brush, '31). Korstian has pointed out that, with larger proportions of silt and clay in the underlying mineral soil, swamp hardwoods are more abundant. Hardwood-cypress swamps are underlain by clay or sandy-clay subsoil. The aspect of the southern white cedar forest has been described and illustrated adequately. Gifford ('00) gave a description of the community in which he emphasized the extreme density of the forest, the trees growing so close together that they afford mutual support and the bases of the crowns meeting to form a solid canopy. He mentioned the dense undergrowth, but neither he nor any of the other workers has analyzed its composition except to note that it consisted of a dense growth of vines and shrubs. Although Harper ('26) listed associated species of all categories, trees, shrubs, lianas, herbs, and bryophytes in order of their abundance in his account of a middle Florida cedar swamp, the cedars were not the largest nor most conspicuous trees in this community. It must therefore be considered as a mixed bog forest which cannot be compared with the true cedar community. Although Korstian and Brush ('31 ) found that pure, dense, more or less even-aged stands are most characteristic f or the southern white cedar, they listed numerous arborescent associates. The number of associated tree species is greater in the southern part of the range than in the northern part. It is apparent from the literature that southern white cedar reproduction requires decidedly open conditions. Pinchot ('00) noted that no reproduction occurs after crowns meet to form a continuous canopy. Korstian and Brush ('31) likewise found that seedlings do not tolerate the shade of the cedar forest. They pointed out that, although the seedlings may start under cover of bog shrubs, the shrubs usually develop rapidly into an impenetrable jungle making establishment of the cedar difficult. Ackerman ('23) found that seedlings come up in abundance in the rollways and tramways after logging, but that elsewhere the slash and the rank growth of shrubs and vines produce a mass which the young cedars have small chance of penetrating. This situation was recognized likewise by Korstian and Brush ('31). It is significant in this connection that in New Jersey the southern white cedar constantly invades cranberry bogs (Gifford, '00). Recognizing the requirement for an open seed bed, at least one free from the extreme competition of the bog shrubs and lianas, several authors suggested clearing to obtain reproduction. In view of the dangers involved in controlled burning in such areas, Ackerman ('23) suggested the use of cat-

Tree vegetation of the forest-tundra ecotone in the Western Sayan mountains and climatic trends

Abstract: Parameters of reproduction of the Siberian stone pine (Pinus sibirica), including radial and apical tree increments, the age structure of stands, the amount of young growth, and its distribution along an altitudinal gradient, have been studied in the forest-tundra ecotone of the Western Sayan. The results show that, over the past 30 years, P. sibirica undergrowth has expanded to the mountain tundra belt, the apical and radial tree increments and stand density have increased, and the life form of many P. sibirica plants has changed from prostrate to erect (single-or multistemmed). These changes correlate with the dynamics of summer temperatures and monthly (in May and June) and annual precipitation. The rise of summer temperatures by 1°C promotes the expansion of P. sibirica undergrowth for approximately 150 m up the altitudinal gradient.

Effect of mixing herbaceous litter with tree litters on decomposition and N release in boreal plantations

Abstract: Background and Aims Abandoned lands are increasingly used to establish fast-growing tree plantations, and are often rapidly colonized by a high density of herbaceous undergrowth These weeds are generally removed since they compete with trees for resources, in particular soil nutrients However, mixing herbaceous litter with the litter of planted trees could also stimulate the activity of decomposers and associated nutrient release due to an increase of litter quality (lower C:N ratio), plant diversity (more diverse litter traits) and water holding capacity The objective was to determine the impact of herbaceous litter on the litter decomposition process of white spruce and hybrid poplar litters alone or in mixtures