The study, published in Discover Forests, represents one of the few genuine long-term reassessments of biomass and carbon storage ever conducted in the tropical dry forests of Central India. A team led by Pranab Kumar Pati of Dr. Harisingh Gour Vishwavidyalaya in Sagar returned in 2025 to the same six forest communities first surveyed in 2001, using the same quadrat-based field protocols to make the two datasets directly comparable. The baseline came from earlier vegetation work in the Pathariya Hills, a rugged outcrop of the lower Vindhyan range built on Deccan Trap basalt, where steep slopes, gullies, ravines and plateaus create a mosaic of soils and habitats that support strikingly different forest assemblages within a small area.

The headline structural finding is stark. Tree density fell from 2,727 individuals per hectare in 2001-02 to 1,347 per hectare in 2025, a statistically significant decline with a large effect size. Yet basal area, the cross-sectional area of all tree stems measured at breast height, barely changed, slipping only marginally from 20.41 to 19.83 square metres per hectare. The explanation lies in the size distribution of the survivors. Mean basal area per tree nearly doubled across the landscape, from 0.0075 to 0.0147 square metres, indicating that the trees that disappeared were overwhelmingly small and young, while the remaining large individuals kept growing and now carry a disproportionate share of the stand’s wood.

That demographic shift is the quiet alarm buried in the data. Dense stands of many small stems have given way to forests dominated by fewer, larger trees, a pattern the authors attribute to selective removal of small and medium individuals and chronic suppression of regeneration under sustained disturbance and grazing. If younger cohorts continue to be depleted, the large residual trees that currently prop up the forest’s basal area, biomass and carbon stocks will eventually age out without replacement, opening canopy gaps, reducing productivity and undermining the ecosystem’s resilience. The structural stability visible today may simply be a lag effect, a demographic imbalance waiting to surface.

The biomass numbers themselves reveal the study’s central paradox. Total biomass across the complex rose from 116.25 to 120.18 megagrams per hectare, a net landscape-level gain of only 3.2 percent that was not statistically significant. But that modest average is the arithmetic of two diverging worlds. At relatively protected Site 1, biomass surged 81 percent, from 28.71 to 151.63 megagrams per hectare, and Site 2 gained 42 percent. At heavily disturbed Site 3, biomass collapsed by half, from 100.87 to 49.57 megagrams per hectare, and Site 6 lost 52 percent, falling from 169.22 to 80.71 megagrams per hectare. Site 4 remained essentially flat. The forest complex is not one carbon store but a patchwork of sinks and sources, and the average erases the difference.

The driver of that divergence is disturbance intensity. Sites 3 and 6 face severe ongoing pressure from logging, lopping, fuelwood extraction, recurrent fire and livestock grazing, with commercially valuable species such as Anogeissus latifolia, Tectona grandis and Santalum album regularly felled illegally. The remaining sites, shielded by stricter Forest Department protection, show no comparable stress. The study’s correlation analysis reinforces the mechanism: basal area was strongly and positively related to total biomass, while stem density showed no significant relationship, confirming that large trees, not tree counts, govern carbon storage in these forests. Where mature individuals are selectively removed, the carbon goes with them.

Species-level analysis adds another layer of concern. Tectona grandis, the teak that characterizes Central Indian dry deciduous forests, contributed the largest biomass gain at 23.09 megagrams per hectare, a recovery the authors link to the gradual strengthening of protection after the extensive teak felling of the 1950s. Butea monosperma, a disturbance-tolerant, fire-resistant, light-demanding species with low palatability to livestock, added 8.23 megagrams per hectare and now dominates the most degraded sites. That dominance is not good news. It signals ecological filtering under chronic disturbance, canopy opening and the progressive loss of shade-tolerant, late-successional taxa, a trajectory toward biotic homogenization in which a handful of resilient species replace a diverse community.

Meanwhile, several ecologically important native species lost ground. Albizia lebbeck, Bridelia retusa, Diospyros melanoxylon, Elaeodendron glaucum, Lannea coromandelica and Madhuca indica all declined in biomass contribution, with losses ranging from roughly 3.8 to 7.6 megagrams per hectare. The authors caution that high biomass in stands increasingly dominated by Butea monosperma should not be mistaken for ecosystem health. Carbon stocks can be partially maintained even as species diversity, functional trait breadth and adaptive capacity erode, leaving the forest less productive, less stable and less able to sequester carbon reliably under future climatic variability.

Methodologically, the study is a model of careful, non-destructive estimation. Aboveground biomass was calculated with the Chave allometric model for tropical dry forests, incorporating field-measured diameters and species-specific wood specific gravity values drawn from an Indian inventory, while belowground biomass followed the Cairns equation for adults and IPCC conversion factors for juveniles. Carbon stocks were derived by applying the standard IPCC carbon fraction of 0.5 to combined above- and belowground biomass. Because the temporal data did not consistently meet assumptions of normality and sample sizes were constrained by the original survey design, the team used the Mann-Whitney U test for temporal comparisons and quantified effect sizes with Hedges’ g, an appropriately conservative approach they acknowledge should be corroborated by larger future samples.

The findings carry clear implications for climate policy and forest management in a country where tropical dry forests cover nearly 42 percent of the total forest area and almost 89 percent of Madhya Pradesh’s forest cover. The authors call for stricter disturbance regulation at the most degraded sites, enrichment planting and assisted regeneration of declining native species, community participation in protection, and the establishment of permanently marked monitoring plots with high-precision georeferencing, which would remove the relocation uncertainties inherent in resampling historical, unmarked quadrats. Quantitative disturbance indices combining field measurements with remote sensing would further sharpen the link between specific pressures and carbon outcomes. The broader lesson is one that resonates far beyond the Pathariya Hills: headline carbon numbers can mask ecological degradation, and protecting the large trees of today means little without safeguarding the recruits that must become tomorrow’s canopy. In the accounting of forest carbon, what survives matters even more than what is stored.

Subject of Research: Long-term changes in forest biomass and carbon stocks in a tropical dry deciduous forest in Central India

Article Title: Temporal dynamics of biomass and carbon stocks over twenty five years in the Pathariya forest complex of Central India

Article References: Pati, P. K., Rajput, N. S., Kaushik, P., Khan, M. L., & Khare, P. K. (2026). Temporal dynamics of biomass and carbon stocks over twenty five years in the Pathariya forest complex of Central India. Discover Forests, 2(1), Article 70. https://doi.org/10.1007/s44415-026-00133-5

Image Credits: AI Generated

DOI: 10.1007/s44415-026-00133-5

Keywords: forest biomass, carbon stocks, tropical dry deciduous forest, Central India, anthropogenic disturbance, tree density, basal area, forest degradation, Butea monosperma, Tectona grandis, carbon sequestration, long-term monitoring

Researchers from Sambalpur University, Terracon Ecotech, and the Government of Odisha set out to quantify litterfall production, standing litter biomass, decomposition rates, and nutrient fluxes in four sacred forests across the region: Andhari, Dedungri, Medha, and Papanga. Three of the sites are dominated by sal (Shorea robusta), while Papanga is dominated by Cleistanthus collinus. The forests lie within a tropical savanna climate zone, where annual rainfall ranges from 900 to 1,400 millimeters, almost all of it delivered during the June-to-September monsoon, and where pre-monsoon temperatures can exceed 45 degrees Celsius. That pronounced seasonality shapes nearly everything that happens on the forest floor.

Between January and December 2023, the team measured litter inputs monthly using one-square-meter collection pits established at least ten meters inside each forest boundary to avoid edge effects. The collected material was separated into leaves, twigs, branches, and miscellaneous fragments, then oven-dried and weighed. Annual litterfall ranged from 8.59 megagrams per hectare per year at Andhari to 11.32 megagrams per hectare per year at Medha, figures that sit comfortably within the global range for tropical forests and actually exceed values reported for several other tropical dry deciduous forests in India. Leaves dominated the mix, contributing between 80.65 and 83.35 percent of total litterfall, followed by twigs, branches, and other material.

The seasonal signal was unmistakable. Litter production peaked in March at all four sites, coinciding with the height of the dry season, when water stress triggers leaf senescence and abscission in deciduous trees. Statistical analysis confirmed that month-to-month variation within sites was highly significant, while differences among the four forests were not. In other words, climate and phenology, not site identity, are the primary engines driving litterfall in these ecosystems. Standing litter biomass followed the same rhythm, accumulating to a maximum in March and dwindling to a minimum during the rainy and post-rainy months of August through November, with annual means ranging from 2.39 megagrams per hectare at Andhari to 2.68 at Medha.

The speed at which that litter disappeared was the study’s most striking finding. Using the classic litterbag technique, the researchers placed 20-gram samples of mixed-species fresh leaf litter, collected during the February-March peak litterfall period, into 20-by-20-centimeter nylon bags with one-millimeter mesh and laid them on the forest floor in a completely randomized design. Six bags were retrieved from each site every month. Roughly 95 percent of the initial litter mass had vanished within six months at every site. The fitted decay constants ranged from 5.75 to 6.65 per year, corresponding to half-lives of just 38 to 44 days. Model-based extrapolation suggested that 99 percent decomposition would be achieved within 274 to 318 days, although the authors caution that these figures extend beyond the six-month observation window.

Litter turnover rates told a similar story. The ratio of annual litterfall to standing litter biomass, a standard index of how quickly organic matter cycles through the forest floor, ranged from 3.59 to 4.22 per year, equivalent to residence times of only 87 to 102 days. Those turnover rates are higher than values reported for tropical semi-deciduous, tropical dry evergreen, and tropical evergreen forests, indicating that these small sacred groves process organic matter unusually fast. The researchers attribute the rapid decay to favorable temperature and moisture conditions during the decomposition period, which stimulate microbial activity, possibly combined with relatively high litter nutrient quality.

That quality question was addressed through chemical analysis of the mixed-species litter. Initial concentrations of nitrogen, phosphorus, and potassium differed significantly among the four forests, with Papanga showing the highest nutrient levels and the most favorable stoichiometric profile. Correlation analyses revealed that initial nitrogen and phosphorus concentrations were significantly associated with decomposition rates, while carbon content was not. The authors note an important caveat: lignin and cellulose, structural compounds that strongly regulate decomposability, were not measured, so the full biochemical picture of litter quality in these forests remains incomplete.

Nutrient release during decomposition followed a clear hierarchy: potassium was lost fastest, followed by nitrogen, then phosphorus. Potassium, highly soluble and prone to leaching, declined rapidly throughout the experiment, with release reaching 98.72 to 99.20 percent across the sites. Nitrogen loss ranged from 92.26 to 95.08 percent, and phosphorus from 80.54 to 95.34 percent after six months. Papanga recorded the highest total nutrient loss at 96.57 percent. Meanwhile, nitrogen and phosphorus concentrations actually increased in the residual litter, a pattern the researchers attribute to microbial immobilization, in which decomposer organisms accumulate these nutrients in their own biomass before releasing them back to the soil. Carbon concentrations remained relatively stable at Andhari and Medha but declined at Dedungri and Papanga.

The study’s authors are candid about its limitations. There were no non-sacred control forests for direct comparison, so the work characterizes variation within sacred forests rather than testing the effects of sacred-forest protection itself. Repeated temporal observations were not analyzed with mixed-effects models, and the correlation results should be read as associations rather than causal claims. Still, the baseline data fill a genuine gap: while litterfall and nutrient cycling have been extensively documented in tropical evergreen forests and, to a lesser degree, in sacred groves elsewhere in India, comparable information for the dry deciduous sacred forests of Western Odisha had been essentially absent.

The implications extend beyond ecology into conservation policy. Sacred forests persist as biodiversity hotspots and providers of ecosystem services, including carbon sequestration, water regulation, and soil conservation, precisely because community restrictions limit timber extraction, grazing, and fuelwood collection. Yet pressures such as fuelwood harvesting, livestock grazing, and non-timber forest product extraction persist to varying degrees, with Andhari and Dedungri showing signs of moderate degradation while Medha and Papanga remain relatively well preserved. By demonstrating that these culturally protected patches sustain high litter production, rapid decomposition, and substantial nutrient turnover, the study provides quantitative evidence that sacred forests function as localized reservoirs of soil fertility in human-dominated landscapes. As land-use intensification continues across tropical India, the researchers argue, protecting these living laboratories of biocultural conservation may be one of the most cost-effective strategies for maintaining nutrient cycling and ecological resilience in dry deciduous landscapes.

Subject of Research: Litterfall production, decomposition rates, and nutrient cycling in tropical dry deciduous sacred forests of Western Odisha, India

Article Title: Litterfall dynamics and decomposition-driven nutrient cycling in sacred forests of Eastern India

Article References: Pradhan, A., Mansingh, A., Gopinath, J. S., & Ekka, N. J. (2026). Litterfall dynamics and decomposition-driven nutrient cycling in sacred forests of Eastern India. Discover Plants, 3(1), Article 412. https://doi.org/10.1007/s44372-026-00892-7

Image Credits: AI Generated

DOI: 10.1007/s44372-026-00892-7

Keywords: litterfall, decomposition, nutrient cycling, sacred forests, tropical dry deciduous forest, Odisha, Shorea robusta, litterbags, soil fertility, ecosystem functioning, biocultural conservation, leaf litter