Determination of the Environmental Factors that Affect the Growth and Survival of Greek Fir Seedlings

Abstract

Forests in the montane-Mediterranean zone have only recently began to be affected by wildfires, therefore the knowledge necessary for restoration projects is missing. The aim of the study was to assess the effects of factors related to seedling attributes, weather conditions and site suitability on seedling performance. The characterisation of sites was based on bedrock and soil clay content as well as pre-fire vegetation. Apical growth and survival of seedlings was monitored for four years in Parnitha National Park. The parameters of a linear mixed model were estimated using annual apical growth of seedlings surviving in the end of the study as the dependent variable and type of site, rainfall, initial seedling height and age as explanatory ones. A quantile regression model using all the data available was estimated for each year of study, taking into account only initial height and site type as well as a logistic regression model of survival. The findings indicate that the growth of Greek fir seedlings depends on May rainfall mediated by soil clay content, which in turn depends on bedrock, which is consistent with the “inverse texture hypothesis”. Sites with low soil clay content were always more beneficial for survival, which was stronger affected by summer–autumn rainfall. In both contexts, drought stress due to soil clay content fades with increasing age. Sites that were not fir dominated prior to fire proved unsuitable also for planting fir seedlings. A minor part of the observed variability could be associated with the initial height of seedlings, especially for seedlings showing high rates of apical growth.

Effects of Seedling Methods on Germination and Growth of Sophora japonica L.

“…The minimum annual growth of direct seeding under a given aspect would be influenced by smaller initial height before transplanting. It is consistent with the conclusion demonstrated by Detsis et al (2020) who found that initial height has significant positive effect on annual growth. However, the positive impact might be offset by insufficiently developed root systems for seedling planting (Wennström et al, 1999; Mollá et al, 2006).…”

“…However, the positive impact might be offset by insufficiently developed root systems for seedling planting (Wennström et al, 1999; Mollá et al, 2006). Additionally, root growth would be limited in the first year after planting because roots outgrowing the seedling cup were removed when transplanting for seedling planting, influencing seedling growth (Detsis et al, 2020; Waiboonya and Elliott, 2020).…”

Long-Term Landscape Dynamics to Assess Land Degradation Hypotheses—An Exploratory Study of Evidence from Travelers’ Narrations

“…The removal of vegetation along with grazing can negatively affect tree seedling establishment and result in an expansion of shrublands and grasslands in previously tree-dominated areas. A change in climate, for example a reduction in early summer rainfall crucial for fir growth [35], may have had similar outcomes.…”

Effect of Seedling Provenance and Site Heterogeneity on Abies cephalonica Performance in a Post-Fire Environment

“…During the summer of 2007, an unpredictable crown wildfire [30] of high-severity [28] completely burned and destroyed a great part (approx. 60%) of the fir forest, resulting in a considerable degradation of the A. cephalonica habitat [6,13,25,26,31]. Due to the species' extremely limited regeneration potential after fire [6], a long-term reforestation project was carried out the next year by the Forest Service of Parnitha in order to restore the burned fir ecosystem.…”

“…Taking into consideration the fact that wildfires were not a common phenomenon in fir ecosystems in the past, many of the above issues concerning post-fire restoration have not been studied at all. Scarce studies have examined the issues pertaining to Greek fir, such as the influence of seedling height and site parameters (shade, competitive vegetation, bedrock, weather conditions) on survival and growth of outplanted A. cephalonica seedlings [25,26]. However, most of the factors affecting reforestation success in a post-fire environment have not been thoroughly studied.…”