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ArticleFarmer-managed natural regeneration (FMNR) on Nigeria's drylands: the influence of changing climate on agroforestry trees management
XV World Forestry Congress, 2-6 May 2022
2022Also available in:
No results found.In Northern Nigeria, prolonged drought critically affects parkland tree regeneration and reduces land productivity and income. However, documentation of parkland trees management in extreme climatic conditions is scarce in the region. Hence, the need to evaluate the management via tree preferences by farmers on Nigeria’s dry agroecological zones (AEZ). To address this, field surveys were conducted in nine villages along a north-south transect, with precipitation increasing southwards through three AEZ of Nigeria: Sudan Savannah (SS), Northern Guinea Savannah (NGS) and Southern Guinea Savannah (SGS). Using Open Data Kit (ODK), information from 92 respondents and 4 focused groups relating to tree regeneration management were collected and aggregated. These include the abundance of the most preferred trees on farms, their regeneration potentials, management and propagation status, as well as usage and land-use constraints. Results showed drought- tolerant species (Parkia biglobosa and Mangifera indica) topped the dominant trees list across the three AEZ, both having 50% more than other agroforestry trees. Though farmers’ management strategies were highly relevant to regeneration and productivity, they did not differ across the zones (P<0.05) except at cropping outside tree canopy cover between SGS and SS using the Kruskal-Wallis test. Positive associations (0.5-0.8) between functions and preference for trees on farms for dominant agroforestry species. Farmers’ adaptation strategy to minimise risk to climate drivers and increase dry forests landscapes resilience made the driest AEZ (SS) had most species on farms and positively impacted the locals' livelihoods. Keywords: Trees, Drought, Farmers, Regeneration, Parklands ID: 3486501 -
ArticleDeveloping simultaneously modeling systems for improving the reliability of tree aboveground biomass- carbon and its components estimates for Machilus odoratissimus nees in the central highlands, Viet Nam
XV World Forestry Congress, 2-6 May 2022
2022Also available in:
No results found.Machilus odoratissimus Nees is a multi-purpose species with, high economic value and environmental protection, so this tree species is commonly used in agroforestry models. In plantation management, it demands modeling systems that predict accurately aboveground biomass- carbon and its components. At the same time, the developed models support computing carbon accumulation of forest trees in agroforestry models for the program of reducing emissions from deforestation and forest degradation (REDD). Twenty-two 300 m2 plots were measured within the full range of 1 to 7 ages in the Central Highlands of VietNam. A total of 22 quadratic mean diameter trees were destructively sampled to obtain a dataset of the dry iomass/carbon of the stem (Bst/Cst), bark (Bba/Cba), branches (Bbr/Cbr), leaves (Ble/Cle), and total tree aboveground biomass/carbon (AGB/AGC). We examined the performance of weighted nonlinear models fit by maximum likelihood and weighted nonlinear seemingly unrelated regression (SUR) fit by generalized least squares for predicting tree aboveground biomass- carbon and its components. The simultaneous estimation of AGB/AGC and its components produced a higher reliability than that of the models of tree components and the total developed separately. The selected forms of modeling systems were AGB = Bst + Bba + Bbr + Ble = a1×(D2H)b1 + a2×(D2H)b2 + a3×Db3 + a4×(D2H)b4 and AGC = Cst + Cba+ Cbr + Cle = a1×(D2H)b1 ++2×(D2H)b2 + a3×Db3 + a4×(D2H)b4 (where D is the diameter at breast height and H is the height of the tree). Keywords: Agroforestry, Machilus odoratissimus, seemingly unrelated regression (SUR), tree biomass- carbon ID: 3472953 -
ArticleAssessment of enrichment planting of teak (Tectona grandis L.f.) in degraded dry deciduous dipterocarp forest in the Central Highlands, Viet Nam
XV World Forestry Congress, 2-6 May 2022
2022Also available in:
No results found.After years of unsustainable logging, dry deciduous dipterocarp forest (DDDF) has become poor in timber stocks and has been converted to industrial crops such as rubber. The objectives of this study were to assess teak (Tectona grandis L.f.) tree establishment under degraded DDDF conditions and to determine factors that influence the suitability of teak as a forest enrichment tree species. A set of 64 experimental plots of 4900 m2 each was set up and observed for 4–5 years for testing enrichment planting with teak under various combinations of two groups of factors: ecological conditions and forest status. Weighted, non-linear, multivariate regression models were used to detect key factors that influenced the suitability of teak. The results showed that at the age of 4 years the average dominant tree height (defined as 20% of the tallest trees in the experimental plot) reached 11.2, 7.8, 5.3 and 3.8 m for very good, good, average, and poor suitability levels, respectively. Survival rates of planted teak from average to very good suitability levels were over 90%. Six key factors that affected the suitability of teak were waterlogging during the rainy season, altitude, stand volume of the degraded DDDF, soil type, percentage of sand and concentration of P2O5 in the soil. Under the extreme ecological and environmental conditions of the DDDF, enrichment planting with teak gave promising results. Keywords: degraded dipterocarp status, dipterocarp enrichment, teak suitability assessment. ID: 3472951
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