Seed Dispersal Models for Natural Regeneration: A Review and Prospects

Abstract

Natural regeneration in forest management, which relies on artificial planting, is considered a desirable alternative to reforestation. However, there are large uncertainties regarding the natural regeneration processes, such as seed production, seed dispersal, and seedling establishment. Among these processes, seed dispersal by wind must be modeled accurately to minimize the risks of natural regeneration. This study aimed to (1) review the main mechanisms of seed dispersal models, their characteristics, and their applications and (2) suggest prospects for seed dispersal models to increase the predictability of natural regeneration. With improving computing and observation systems, the modeling technique for seed dispersal by wind has continued to progress steadily from a simple empirical model to the Eulerian-Lagrangian model. Mechanistic modeling approaches with a dispersal kernel have been widely used and have attempted to be directly incorporated into spatial models. Despite the rapid development of various wind-dispersal models, only a few studies have considered their application in natural regeneration. We identified the potential attributes of seed dispersal modeling that cause high uncertainties and poor simulation results in natural regeneration scenarios: topography, pre-processing of wind data, and various inherent complexities in seed dispersal processes. We suggest that seed dispersal models can be further improved by incorporating (1) seed abscission mechanisms by wind, (2) spatiotemporally complex wind environments, (3) collisions with the canopy or ground during seed flight, and (4) secondary dispersal, long-distance dispersal, and seed predation. Interdisciplinary research linking climatology, biophysics, and forestry would help improve the prediction of seed dispersal and its impact on natural regeneration.

Role of dispersal in the altitudinal migration of Pinus hartwegii and Abies religiosa in mountain systems

“…dispersal within a canopy (Kim et al, 2022). Contrary to what we considered in our second hypothesis, the elevation by itself was not determinant in the frequency of LDD events, but various factors participated such as the vertical component and the horizontal component of the wind speed, the direction of the wind and the site from which the seeds were released.…”

“…Variation in diaspore morphological traits can have significant impacts on wind dispersal distributions when comparing species (Kim et al, 2022). Our results suggest that even though the seeds of Abies religiosa and Pinus hartwegii have similar appendages to assist in wind dispersal, the two species differ in their dispersal potential.…”

Stand structure dynamics and effect evaluation after thinning

“…In the LT treatment, one unanticipated nding was that the stand regeneration was effective and the regenerated trees were almost surrounded by the same species. As seeds are limited in their range of dispersal, the regenerated trees tend to be distributed around their mothers (Kim et al, 2022).…”

What is the value of biotic seed dispersal in post‐fire forest regeneration?

“…This might hinder the success of plantations and highlights the important complementary role of natural regeneration from burnt and neighboring areas (Jordan et al., 2019). In turn, the success of natural regeneration is highly variable as it depends on fire intensity, the presence of plant adaptations to survive wildfires, the quality of the seed bank, the proximity of unburnt areas that can supply propagules, and on the activity of natural seed dispersers (Busby & Holz, 2022; Kim et al., 2022). Therefore, the relative importance of different fire‐coping strategies, such as resprouting (Moreira et al., 2009) and assisted recolonization through seed dispersal, will ultimately depend on a multitude of drivers, including floristic composition, landscape configuration, and fire intensity and frequency (Keeley et al., 2005).…”