Many bamboo species are well suited for agroforestry as they are more versatile and rapidly renewable than trees. Bamboo is an important income source for rural villagers around the world, especially in tropical developing countries, such as Lao PDR (Lao People’s Democratic Republic). This study applied a value chain approach to compare potential incomes from different bamboo utilization models: (1) existing model of selling semi-processed raw materials (bamboo splits), and (2) new model of producing handcraft products locally. Using a rural village in eastern Lao PDR (Nongboua village in Vientiane Capital province) as a case study, we provided empirical assessments of two bamboo value chains. Based on interviews with the villagers and stakeholders and government statistical data from 2017 to 2019, existing and new bamboo production chains were evaluated. In the existing value chain, the final products, bamboo chopsticks, are worth $6.74/kg. The value chain starts with bamboo harvesting, collection, and management, which are done by villagers in Lao PDR and taxed by the Lao PDR government. Bamboo splits are then transported to Vietnam to make the final products to sell. Local villagers received only 4.9% of the total value. The new bamboo handicraft model could produce 9 bamboo cups and 60 medals from one bamboo stem worth $52.6–61.7 and $343.8. In this value chain, bamboo harvesting, management, and processing to final products are done by villagers. The handcrafts were collected by traders to be sold at souvenir shops. Local villagers could capture 29.4%–42.3% of the total values. Producing bamboo cup and medal could generate 1.12–2.17 and 234.8–244.6 times higher income for villagers per labor hour and per bamboo stem, respectively, and allow them to use more bamboo resource than producing bamboo splits to export to Vietnam. If applied to other rural areas in Lao PDR, the new bamboo product model for handicrafts can be a better income source for local villagers in Lao PDR with sustainable use of bamboo resources than the existing model. However, it requires extensive bamboo handicrafts training over a year. Although alternative uses of bamboo would be different depending on social, economic, and market contexts, the value chain analysis demonstrated in this study can be applied elsewhere to increase local retention of economic values generated from agroforestry.

The quantification of urban tree biomass allocation has primarily relied on estimations using allometric equations (AEs) developed for nondestructive harvest methods. However, the lack of harvest-based AEs that account for belowground biomass, nutrient concentration, and annual growth rates poses challenges in accurately quantifying the greenhouse gas inventory for urban land uses. In this study, we aimed to develop AEs using a log-transformed linear model for eight urban landscaping tree species, taking into account belowground biomass. We purchased 117 urban landscaping trees from tree farms in South Korea and investigated their biomass fractions, carbon and nutrient concentrations, and annual growth rate using a destructive method. We also developed AEs for different tree compartments using diameter at breast height as an independent variable. The AEs obtained exhibited high suitability, as evidenced by their high R² values (0.853–0.982 and 0.806–0.923 for aboveground and belowground biomass, respectively). The mean belowground biomass fraction across the different species was approximately 30%, suggesting that urban trees could allocate more belowground biomass than forest trees. Conversely, carbon and nitrogen concentrations varied significantly across species and compartments, and the mean annual carbon sequestration rate was 3.96 kg C year⁻¹ tree⁻¹. Therefore, the application of the AEs for urban trees may enhance the accuracy of the national greenhouse gas inventory for the settlement sector.

Urban trees grow in diverse environments where site conditions and human management may influence their growth patterns. However, few allometric equations (AEs) have been developed for urban trees, and the effects of environmental variations across urban land use categories on tree biomass remain largely unexplored. Therefore, this study developed urban land-use-specific AEs for major urban tree species in South Korea. We selected eight major urban tree species groups (at genus level), harvested 201 trees, and non-destructively measured the stem volumes of 1995 trees using a laser dendrometer. Species-specific and generalized AEs to estimate stem volume were developed under three urban land use categories: street trees, urban parks, and others. The results indicated that differences in stem volume across urban land use categories varied by species, with street trees generally showing smaller stem volumes. Furthermore, due to the high variation in stem volume within species, sampling designs that encompass diverse size distributions are necessary when developing AEs for urban trees. Our findings indicate that various factors in urban environments influence tree volume and considering these differences is essential for improving biomass estimation accuracy.

The national level carbon sequestration estimation for urban trees generally relies on diameter at breast height (DBH) increments. However, limited research on urban tree growth has led to uncertain estimates. In this study, we determined the DBH increment of six major urban tree species in South Korea using three analytical methods (mean, linear regression, and generalized additive model) and two data classifications (total and segmented). Additionally, wedeterminded the aboveground woody biomass (AGWB) increment, which was calculated using the estimated DBH increment, and the accuracy of the estimates using different methods. We found wide variations in DBH increment (0.616 to 1.002 cm yr⁻¹) among the assessed tree species. Metasequoia glyptostroboides exhibited the highest mean growth, while Pinus densiflora showed the lowest. The peak DBH increment occurred at a median of 25.4 cm for Quercus spp. and 40.0 cm for Prunus yedoensis. The total mean method led to overestimations of AGWB increment, especially for the largest trees (i.e., those in the top 5% of DBH). Our study suggests that relying on a simple total mean method can lead to significant uncertainties in estimating AGWB increment. Therefore, more accurate methods for estimating DBH increment, especially in urban environments, are needed.