Relative importance of various regeneration mechanisms in different restoration stages of Quercus variabilis forest after selective logging

Yaoqin Xue,Wenhui Zhang,Liwei Ma,Jianyun Zhou,Chuang Ma

doi:10.5424/fs/2014232-03263

Abstract

Aim of study: Quercus variabilis (Chinese cork oak) reproduces asexually and sexually. This study aimed to determine the status and growth of asexual and sexual recruits of Q. variabilis in different forest recovery stages.Area of study: Three selective logged stands and one unlogged stand in Q. variabilis forest, Shaanxi Province, China.Material and Methods: Origin, number, basal diameter, height and size structure of Q. variabilis shoots (height ≤200 cm) were investigated in the plots of 5, 10, and 20-years post-logging stands and unlogged stand. Effects of recovery stage on the density and growth of the three original recruits (stump sprouts, stem base sprouts and true seedlings) were analysis by One-way ANOVA.Main results: Sprouts dominated logged stands, whereas true seedlings dominated unlogged stand, stem base sprouts only existed in 20-years post-logging and unlogged stands. Stump sprout density and sprout number per stump both declined with extended post-logging time. True seedlings density increased from 7 to 20 shoots/100 m2 as the postlogging time extended, and peaked in unlogged stand (94 shoots/100 m2). An ongoing size structure was observed in true seedlings in all stands. Stump sprouts were taller and greater than true seedlings.Research highlights: Stump sprouts contributed more to Q. variabilis forest recovery in the early stage after disturbance. The contribution of true seedlings was limited in the same stage, but they were beneficial for population long-term development. Stem base sprouts were most likely to be a survival strategy rather than a reproductive strategy.Key words: asexual reproduction; true seedling; post-logging time; Chinese cork oak.

Highlights

The natural recovery of disturbed forests may be initiated through sexual and asexual mechanisms
This study revealed the presence of both asexual and sexual regeneration recruits for Chinese cork oak in the southern area of Qinling Mountains
Asexual shoots were the predominant recruits of Chinese cork oak in the logged stands, whereas true seedlings were predominant in the unlogged stand

Summary

Introduction

The natural recovery of disturbed (logged, burned, slashed, and damaged by hurricane) forests may be initiated through sexual and asexual mechanisms. Sexual and asexual recruits are both essential in forest recovery, but differ in individual survival and growth rate, dispersal distance, phenology of offspring production, and establishment (Winkler and Fischer, 2002; Beaudet and Messier et al, 2008). Germinated seeds in soil seed bank, suppressed seedlings, and sprouts from existing roots or stems may be initial recovery recruits (Hoffmann, 1998; Kammesheidt, 1998, 1999; Yamada and Suzuki, 2004; Simões and Marques, 2007; KyDembele et al, 2007). Sprouts grow fast but their dispersion is limited by the parent plant, whereas true seedlings can disperse far (Hoffmann, 1998; Winkler and Fischer, 2002). Asexual sprouting may result in several individuals (clones) originating from one parent plant and occupying its niche persistence, thereby improving individual survival and resistance (Miller and Kauffman, 1998; Bond and Midgley, 2001; Beaudet and Messier et al, 2008)

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