The influence of fencing on seedling establishment during reforestation of oak stands: a comparison of artificial and natural regeneration techniques including costs

Abstract

In temperate Europe, oak-dominated forests are widespread, supporting high biodiversity and providing important ecosystem services. Insufficient natural regeneration has, however, been a concern for over a century. The objective of this study was to gain insights into differences in regeneration success using artificial and natural regeneration techniques for reforestation of oak (Quercus robur L.) stands. We monitored seedlings following planting, direct seeding and natural regeneration over five years in a randomized block experiment in southern Sweden with fenced and non-fenced plots. Fencing had a strong positive effect on height growth, especially for planted seedlings that were taller than the other seedlings and more frequently browsed in non-fenced plots. In contrast, there was little effect of fencing on survival, establishment rate and recruitment rate of seedlings. Due to aboveground damage on seedlings from voles, protection of acorns did not improve establishment rate following direct seeding. Under current circumstances at the site with a sparse shelterwood of old oaks, we conclude that natural regeneration was the most cost-efficient regeneration method. It resulted in the most seedlings at the lowest cost. However, regeneration success was heavily influenced by interference from herbaceous vegetation. With a small additional investment in vegetation control, the results might have been improved for planting and direct seeding.

Chances and Limitations of Mixed Oak Regeneration under Continuous Canopy Cover—Evidence from Long-Term Observations

“…Equally apparent was the potential of natural oak regeneration, which was the basis of the observed oak regeneration in the majority of stands. Together with the findings by Löf et al [41], who evaluated the costs for oak natural regeneration and found them to be the lowest, this results in an additional potential for operational savings or at least compensation.…”

“…However, Ligot et al [34] demonstrated that beech outperformed oak throughout the light gradient and concluded that silvicultural control of the canopy cover is not sufficient in mixed oak and beech regenerations. Consequently, to keep survival rates high the management of mixed oak regenerations has to consider competing woody species [37,38] and ground vegetation [39][40][41].…”

Fencing improves the establishment and growth of Boswellia papyrifera (Del.) Hochst wildlings

“…For instance, Habrova and Pavlis (2017) observed an increasing rate of seedling survival and development for Dracaena cinnabari with increasing time of their exclosure on the Firmihin Plateau, Socotra Island, Yemen. Similarly, Löf et al (2021) reported a significant height increment in both planted and naturally regenerated Quercues robur seedlings within fenced areas compared to non-fenced areas.…”

A new methodology to evaluate natural regeneration: A case study of Quercus ilex in the montado in Portugal

“…The third criterion evaluates the height of the regeneration individuals in two classes: (1) individuals with a height between 0.5 and 1.3 m and (2) individuals with a height higher than 1.3 m. It can be considered a surrogate of the sapling's development. The height of the saplings is the parameter more described in the previous literature (Long and Jones, 1996;Harmer, 2005;Dobrowolska, 2006;Esquivel et al, 2007;Löf et al, 2021). The fourth criterion evaluates the diameter of regeneration individuals measured at 1.30 m, that is when the regeneration tree can be considered installed (when it overcomes the period of high mortality rate) (Assmann, 1970).…”

“…characteristics. Most regeneration studies evaluate regeneration by quantifying its density and height (Harmer, 2005;Acácio et al, 2007;Barrere et al, 2021;Bolibok et al, 2021;Löf et al, 2021). The traits of the individuals are not evaluated.…”