Agroforestry systems (AFS) and practices followed in India are highly diverse due to varied climatic conditions ranging from temperate to humid tropics. The estimated area under AFS in India is 13.75 million ha with the highest concentration being in the states of Uttar Pradesh (1.86 million ha), followed by Maharashtra (1.61 million ha), Rajasthan (1.55 million ha) and Andhra Pradesh (1.17 million ha). There are many forms of agroforestry practice in India ranging from intensified simple systems of monoculture, such as block plantations and boundary planting, to far more diverse and complex systems, such as home gardens. As a result, the biomass production and carbon sequestration potential of AFS are highly variable across different agro-climatic zones of India. Studies pertaining to the assessment of biomass and carbon storage in different agroforestry systems in the Indian sub-continent are scanty and most of these studies have reported region and system specific carbon stocks. However, while biomass and carbon stock data from different AFS at national scale has been scanty hitherto, such information is essential for national accounting, reporting of C sinks and sources, as well as for realizing the benefits of carbon credit to farmers engaged in tree-based production activities. Therefore, the objective of this study was to collate and synthesize the existing information on biomass carbon and SOC stocks associated with agroforestry practices across agro-climatic zones of India. The results revealed considerable variation in biomass and carbon stocks among AFS, as well as between different agro-climatic zones. Higher total biomass (>200 Mg ha⁻¹) was observed in the humid tropics of India which are prevalent in southern and northeastern regions, while lower total biomass (<50 Mg ha⁻¹) was reported from Indo-Gangetic, western and central India. Total biomass carbon varied in the range of 1.84 to 131 Mg ha⁻¹ in the agrihorticulture systems of western and central India and the coffee agroforests of southern peninsular India. Similarly, soil organic carbon (SOC) ranged between 12.26–170.43 Mg ha⁻¹, with the highest SOC in the coffee agroforests of southern India and the lowest in the agrisilviculture systems of western India. The AFS which recorded relatively higher SOC included plantation crop-based practices of southern, eastern and northeastern India, followed by the agrihorticulture and agrisilviculture systems of the northern Himalayas. The meta-analysis indicated that the growth and nature of different agroforestry tree species is the key factor affecting the carbon storage capacity of an agroforestry system. The baseline data obtained across various regions could be useful for devising policies on carbon trading or financing for agroforestry.

Himalayan forest has been threatened by rapid anthropogenic activities, resulting in the loss of forest diversity and climate change. The present study was carried out on four aspects (northern, southern, western and eastern), at three different altitudinal ranges, namely, 1000–1300 m above sea level (m a.s.l.), 1300–1600 m a.s.l. and 1600–1900 m a.s.l., and at three diverse mountain ranges (Kalaghat, Barog and Nangali) of sub-temperate forest ecosystems of the mid Himalayan ranges, to elucidate their influence on vegetation, tree characteristics and ecosystem carbon density. The results revealed that Pinus roxburghii is the most dominant forest community of the mid Himalaya’s forest, irrespective of altitudinal gradient and slope. The south-facing slopes are occupied by the xerophytic tree species frequently found in the lower Shiwalik P. roxburghii forest, whereas the north-facing ones are dominated by mesophyllic species, such as Cedrus deodara and Quercus leucotrichophora, which commonly grows in the northwestern Himalayan temperate forest ecosystem. The maximum stem density (211.00 Nha⁻¹) was found at 1000–1300 m a.s.l., and on the northern aspect (211.00 Nha⁻¹). The maximum stem volume (236.50 m³ ha⁻¹) was observed on the northern aspect at 1000–1300 m a.s.l., whereas the minimum (32.167 m³ ha⁻¹) in the southern aspect at 1300–1600 m a.s.l. The maximum carbon density (149.90 Mg ha⁻¹) was found on the northern aspect and declined with increasing elevation from 123.20 to 74.78 Mg ha⁻¹. Overall, the study establishes that the southern and western aspects are very low in carbon density, whereas the northern aspect represents higher biodiversity as well as carbon and nutrient stocks. Therefore, aspect and altitude should be given due importance for efficient managing of biodiversity and mitigating climate change.

Carbon stock estimation in different land use systems is necessary for curbing global climatic crisis. In the present study, high-altitude dry temperate land use systems (LUS) at three altitudinal ranges “A_1, 1900–2170 m.a.s.l., A_2, 2170–2440 m.a.s.l., and A_3, 2440–2710 m.a.s.l.” were selected based on lapse rates in Kinnur district of Himachal Pradesh, India. The study was aimed at estimating the difference in biomass and carbon stocks in different land use systems and recommendation of the suitable environment-friendly land use for the region. Six land use systems viz.; agriculture, horticulture, agrihorticulture, agri-horti-silviculture, silvipasture, and barren land common at all the three altitudes were selected for experimental setup. Maximum mean aboveground biomass (84.65 t ha^− 1), belowground biomass (19.50 t ha^− 1), and total biomass (104.10 t ha^− 1) were recorded in the silvipasture land use system. Total biomass production of different land use systems followed the order: silvipasture > agri-horti-silviculture > agrihorticulture > horticulture > agriculture > barren land respectively. Maximum soil organic carbon (1.41%) was recorded in silvipasture land use systems, which however remained statistically at par with the organic carbon contents of horticulture. Soil organic carbon, irrespective of the land use system increased with increase in altitudinal range and decreased with increase in soil depth. Maximum carbon density (155.77 t ha^− 1) in 0–100 cm layer was in agri-horticulture LUS. The order of carbon density under different land use systems was agri-horticulture > agri-horti-silviculture > silvipasture > horticulture > agriculture > barren land. Irrespective of the land use system, the carbon density at different altitudinal gradient followed the trend A₁, 1900–2170 m.a.s.l., > A₃, 2440–2710 m.a.s.l and > A₂, 2170–2440 m.a.s.l. The outcome of the study can play an important role, while selecting different land use systems and different crop combinations for effective management of carbon budget to mitigate climate change and global warming issues in other fragile Himalayan ecosystems.

Multipurpose tree species are recognized as an important fodder source for livestock, but their potential remains untapped due to dearth of knowledge about their nutritive value. Therefore, 15 MPTs, i.e.,Acacia catechu,Albizia chinensis,Bauhinia variegata,Celtis australis,Ficus roxburghii,Grewia optiva,Leucaena leucocephala,Melia composita,Morus serrata,Olea glandulifera,Ougienia oojeinensis,Pittosporum floribundum,Quercus glauca,Q.leucotrichophoraandSalix tetraspermawere evaluated for nutritional characteristics, relative nutritive value index (RNVI), palatability index and farmers’ preference on a seasonal basis in north-western Himalayas mid-hills. Most of the nutritive and mineral content decreased as leaves matured with the exception of ether extract, calcium, copper, organic matter and carbohydrate content, while cell-wall constituents and anti-nutritional contents increased. Overall,M.serratahad the highest RNVI in spring and summer, whileG.optivaduring autumn and winter. Similarly,L.leucocephalahad the highest palatability (97.86%), whileM.composita(38.47%) had the lowest one. Additionally,G.optivawas the most favored MPT for livestock among farmers, whileM.compositawas the least ones. The outcome of the study will help policy makers, planners and farm managers in establishing large scale plantations of highly nutritious and palatable species, likeG.optiva,L.leucocephala,B.variegata, andM.serratafor year-round supply of green leaves and as a supplement to low-quality feed.