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Meta-analysis of livestock effects on tree regeneration in oak agroforestry systems
Publication . Ibne Wadud, Abdullah; Bugalho, Miguel N.; Vaz, Pedro Gonçalves
Livestock grazing occupies over a quarter of terrestrial land and is prevalent to agroforestry ecosystems,
potentially affecting the survival, growth, and density of trees’ early developmental stages, such as seeds,
seedlings, and saplings. To address the effects of livestock on tree recruitment in the face of ongoing debates
about their impacts, we conducted a 33-year meta-analysis in Quercus-dominated agroforestry systems. Our
analysis revealed a consistently negative effect of livestock on oak acorns, seedlings, and saplings. Significantly,
livestock body size influenced oak regeneration, with small-sized livestock, notably sheep and goats, having a
more pronounced negative impact compared to mixed-size systems, mainly involving cattle and sheep. The ef-
fects of small-sized livestock were markedly detrimental on acorn survival and seedling/sapling density,
although no studies eligible for meta-analysis examined large livestock impacts on acorns. Overall, mixed-size
livestock systems, often involving cattle and sheep, lessen the negative effects. Our findings indicate that the
body size and foraging behaviors of livestock should be considered for the ecological sustainability of the tree
component in agroforestry systems. While protective measures have long been integral to well-managed agro-
forestry systems, our results underscore the importance of integrating diverse livestock sizes and applying spe-
cific protective strategies, particularly for acorns and saplings, to further refine these practices. Future research
should expand to underrepresented regions and livestock types to refine global agroforestry management
practices.
Encouraging Invasive Acacia Control Strategies by Repurposing Their Wood Biomass Waste for Pulp and Paper Production
Publication . Neiva, Duarte M.; Godinho, Maria C.; Simões, Rogério M. S.; Gominho, Jorge
Concerns on the expanding infestation of several Acacia species in the southern Mediter-
ranean European countries have triggered an ever-growing requirement for costly targeted control
actions. Valorizing biomass waste produced could help promote and better finance these actions.
For that purpose, wood wastes from invasive control actions were tested regarding their pulp and
paper potential, aiming to entice cellulose industries to partake in future conservation actions. Wood
waste from the five most pervasive Acacia species was studied (Acacia dealbata Link, Acacia longifolia
Willd, Acacia mearnsii De Wild, Acacia melanoxylon R.Br, and Acacia saligna Labill) regarding physical
and chemical characteristics, and a central composite design was used to optimize alkali charge and
reaction temperature on pulping yield and delignification. Bleached kraft pulps were produced with
each species’ optimized conditions and for an equitable mixture of all species. Optimized pulp yields
(52.6%–53.5%) and pulp polymerization degree (2867–3690) of Acacia species were higher than those
of Eucalyptus globulus Labill (used as reference). Optimized bleached pulps were refined and fiber,
pulp, and handsheet properties determined. Acacia dealbata and A. longifolia presented high specific
wood consumption and lower handsheet strength properties, pointing to overall lower pulping
potential, while A. melanoxylon and A. mearnsii characteristics were equal to or higher than those of
E. globulus. A. saligna pulp and handsheet characteristics appear more suited for tissue paper. The
Acacia mixture achieved acceptable characteristics, enabling the indiscriminate use of Acacia wood
regardless of the species. As a shortcoming, the Acacia pulps showed the worst optical characteristics,
with brightness dropping substantially with beating (64%–76%) when compared to E. globulus (81%).
A remote sensing assessment of oak forest recovery after postfire restoration
Publication . Lopes, L. F.; Dias, F. S.; Fernandes, P. M.; Acácio, V.
Mediterranean Europe is experiencing a rise in severe wildfires, resulting in growing socioeconomic and ecological impacts.
Postfire restoration has become a crucial approach to mitigate these impacts and promote ecosystem recovery. However, the
ecological effects of such interventions are still not well understood. We employed remote sensing techniques to evaluate
the impact of postfire emergency stabilization on the recovery of deciduous oak forests in Portugal. Our study encompassed
3013 sampling points located in areas with and without postfire interventions. We chose the Normalized Difference Vegeta-
tion Index (NDVI) as an indicator of oak forest recovery over a four-year period following wildfires that took place in 2016
and 2017. We used a Generalized Additive Mixed Model (GAMM) to assess how NDVI changed over time as a function
of postfire restoration, fire characteristics, topography, and postfire drought events. We found that postfire restoration had a
significant positive effect on NDVI recovery over time, although this effect was small. Severe drought and fire recurrence up
to six fires had a negative effect on the recovery of NDVI. Conversely, severe wetness and either low or high burn severities
had a positive effect on recovery. Our study emphasizes the importance of monitoring postfire restoration effects on forest
recovery to guide restoration planning and improve forest management in burned areas. This becomes even more relevant
under increased wildfire severity predicted for the Mediterranean region interacting with other climate-driven disturbances,
which will further negatively affect forest recovery.
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Entidade financiadora
Fundação para a Ciência e a Tecnologia
Programa de financiamento
Concurso de avaliação no âmbito do Programa Plurianual de Financiamento de Unidades de I&D (2017/2018) - Financiamento Base
Número da atribuição
UIDB/50027/2020