Understory Structure and Vascular Plant Diversity in Naturally Regenerated Deciduous Forests and Spruce Plantations on Similar Clear-Cuts: Implications for Forest Regeneration Strategy Selection

Abstract

Abstract:The active effect of natural regeneration on understory vegetation and diversity on clear-cut forestlands, in contrast to conifer reforestation, is still controversial. Here we investigated differences in understory vegetation by comparing naturally regenerated deciduous forests (NR) and reforested spruce plantations (SP) aged 20-40 years on 12 similar clear-cuts of subalpine old-growth spruce-fir forests from the eastern Tibetan Plateau. We found that 283 of the 334 vascular plant species recorded were present in NR plots, while only 264 species occurred in SP plots. This was consistent with richer species, higher cover, and stem (or shoot) density of tree seedlings, shrubs, and ferns in the NR plots than in the SP plots. Moreover, understory plant diversity was limited under dense canopy cover, which occurred more frequently in the SP plots. Our findings implied that natural deciduous tree regeneration could better preserve understory vegetation and biodiversity than spruce reforestation after clear-cutting. This result further informed practices to reduce tree canopy cover for spruce plantations or to integrate natural regeneration and reforestation for clear-cuts in order to promote understory vegetation and species diversity conservation. OPEN ACCESSForests 2014, 5 716

Effects of natural broadleaved regeneration vs conifer restoration on the herb layer and microclimate

“…These features are: the number of species decreases during understory establishment and growth declines compared with the Douglas-fir plantation, and the domination of shade-tolerant species characteristic of beech forests [55,56]. Although current insight into reforestation with indigenous trees emphasizes its important role in biodiversity conservation [23,[59][60][61], we have not recorded any non-indigenous herbaceous plant species in the Douglas-fir plantation. Therefore, regarding the naturalness of the herb layer, in the modern and sustainable forest management the decision to use the conifer species on former deciduous species soil is much more important than the decision to reforest with native or non-indigenous tree species.…”

“…The ecological roles of the herb layer and their importance could be summarized by five aspects: (i) contribution to forest biodiversity; (ii) as the site of initial competitive interactions important to the regeneration of dominant canopy species; (iii) its link with the overstory; (iv) its role in ecosystem functions (e. g. energy flow, nutrient cycling); and (v) its abilities to respond to various disturbances, both natural and induced by direct and indirect human activities [11]. A large number of species, easy assessment in the field, specific site requirements and the ability to respond to disturbances and different forest management decisions make the forest herb layer the most suitable indicator of the forest site conditions, environmental changes, forest dynamics and human impact [5,6,[12][13][14][15][16][17][18][19][20][21][22][23][24]. Numerous site-related factors, both biotic and abiotic, affect herbaceous plant communities in forests [3,[25][26][27][28][29].…”

Surrounding vegetation matters for arthropods of small, natural patches of indigenous forest

“…Natural forests, which mostly occur in areas of high rainfall, are characterised by structurally complex vegetation (Eeley et al ., ; Robson et al ., ; Joseph et al ., ; Fang et al ., ). They also serve as a conservation priority for arthropod biodiversity (Lawes et al ., ).…”

Canonical Correlation Analysis across Vegetation and Soil Properties of the Disturbed and Undisturbed Coastal Forest Ecosystems

“…Seventy (70) small quadrants of 25 m × 25 m size were established for collection of adult tree data. Within these plots, 2 m × 2 m subplots were established for collection of seedlings, saplings and shrubs data [33,34]. From these plots, stems with a diameter of ≥ 20 cm at breast height (dbh) (approximately 1.34 m above the ground) were categorized as tree species.…”