Disentangling the Relationship between Tree Biomass Yield and Tree Diversity in Mediterranean Mixed Forests

Abstract

Tree biomass and the diversity relationship in mixed forest have an impact on forest ecosystem services provisions. Tree biomass yield is driven by several aspects such as species identity, site condition, stand density, tree age and tree diversity expressed as species mingling and structural diversity. By comparing diverse degrees of tree mixtures in natural forests, we can gain insight into the ecosystem services provision level and dynamic. Two monitoring sites in the Castilian Northern Plateau (Spain) have been analyzed to disentangle the relationships between biodiversity levels and tree biomass yield. Two permanent one hectare (ha) squared plots were established at Llano de San Marugán and Valdepoza. In each plot, all individual trees were measured (diameter and height), georeferenced and its species identity defined. Tree species in the two sites were Pinus sylvestris, Pinus nigra, Pinus pinea, Quercus pyrenaica, Quercus ilex, Quercus faginea and Juniperus thurifera. From these datasets, ten diversity indices that fall in three categories (species richness indices, species compositional/mingling indices and vertical structural indices) were used as predictor variables to fit several candidate models. By merging the trees by site (without considering the species identity) selected models include individual tree basal area as an explanatory variable combining by addition or interaction with diversity indices. When species are analyzed independently, structural diversity impacts on biomass yield in combination (additive or multiplicative) with tree size is negative for Pinus nigra and positive for the other species.

Disentangling the relationship of aboveground biomass, structure and tree diversity in a mixed Acacia plantation in Northern Vietnam

“…The relationship between tree biomass and diversity can also vary among the species analyzed. (Chen and Klinka 2003;Lindén and Agestam 2003;Baeten et al 2019;Bravo et al 2021).…”

Use of Terrestrial Laser Scanning (TLS) on crown and stem measuremntens in the survey and monitoring of mixed forests

“…Our results suggest interactions in these pineoak mix forests which reduced competition, which may involve a complementary and efficient use of resources over time (Forrester, 2014) between shade-tolerant and shade-intolerant species (McElhinny et al, 2005;. Also, explained by differences in foliage persistence during the year (Bravo et al, 2021), which may also cause changes in tree species' crown allometry (Toïgo et al, 2018), creating inter-specific variations in crown architecture and height, when combining species with different shade tolerances or vertically-oriented species with more laterally expanding tree species (Ammer, 2019;Pretzsch & Schütze, 2014).…”

“…Under potential global warming effects, forest research has experimented with a shift from monospecific to more complex forest stands e.g. Aldea, 2018; Bravo-Oviedo et al, 2014;Bravo et al, 2021;Cattaneo et al, 2020;del Río et al, 2018del Río et al, , 2019Merlin et al, 2015;Pretzsch & Schütze, 2021;Riofrio, 2018), not only because several studies have proved high biodiversity level is linked to mixed forests with high forests productivity (Bayer, Seifert, & Pretzsch, 2013;Forrester & Bauhus, 2016;Liang et al, 2016; compared to monocultures (Pretzsch & Schütze, 2014;Riofrío et al, 2017), but also because these stands present some advantages over monospecific ones concerning ecological functions and services (Forrester, 2017;, showing to be more resilient, resistant, and recover faster from storms (Bravo et al, 2021;. Most recently, Rodríguez De Prado et al( 2022), proved, as well, that growth rates for mixed stands were higher than in pure stands.…”

“…Since its implementation in forestry science, many authors have developed different studies based on mixed forest structures (e.g. (Martin-Ducup et al, 2016;Pretzsch & Zenner, 2017;Seidel et al, 2011;Wei et al, 2016) as species identity modifies the mixture outcomes (Bravo et al, 2021). This is why it is so necessary to study all possible species mixtures to define an appropriate management strategy for each species composition (Bravo et al, 2021) based on accurate and numerical analyses.…”

“…The crown is a fundamental element of a tree, accomplishing multiple functions (W. Lin et al, 2017). For instance, crown size is closely related to the photosynthetic capacity of a tree (Hardiman et al, 2011;Hemery et al, 2005) and it may reflect the outcome of interspecific interactions (Seidel et al, 2011), looking to fully utilize limiting resources in different space and time (Bravo et al, 2021).…”