Effect of Spacing on Growth Performance, Microclimate and Soil Health of Micro Forests under Punjab Conditions, India

The present work was carried out in the Punjab Agricultural University, Ludhiana during 2022-23 to evaluate the impact of spacing on growth performance, biomass accumulation, microclimate modulation, and soil health of micro forests under Punjab conditions. A factorial randomized block design was used, involving 15 native plant species planted at two different spacings (1 m × 1 m and 1.5 m × 1.5 m). The results showed that Melia azedarach exhibited superior growth across all parameters, including plant height (518.52 cm), basal diameter (48.93 mm), crown spread (275.11 cm) and total biomass (66.19 t ha-1) followed by Albizia lebbeck. The micro forest established with 1 m × 1 m spacing significantly improved soil health and microclimate better in comparison to 1.5 m × 1.5 m spacing. This configuration also resulted in higher biomass accumulation (47.70 t ha-1). In contrast, the 1.5 m × 1.5 m spacing promoted greater basal diameter (45.75 mm) and crown spread (155.19 cm) but resulted in lower biomass accumulation (28.44 t ha-1). Based on the findings, the study recommends the planting of native fast-growing species such as Melia azedarach, Albizia lebbeck, Dalbergia sissoo, Vitex negundo, and Morus alba at closer spacing to enhance urban ecological restoration, improve soil health, and mitigate the adverse effects of urbanization. Conversely, the inclusion of slow-growing species such as Madhuca longifolia and Aegle marmelos is discouraged under such dense planting conditions.