Journal of Forest Science, 67, 2021 (3): 101–112 Original Paper https://doi.org/10.17221/124/2020-JFS Impact of silvicultural system on natural regeneration in Western Himalayan moist temperate forests of Pakistan Javed Iqbal 1,2* 1Department of Silviculture, Faculty of Forestry and Wood Sciences, Czech University of Life Sciences Prague, Prague, Czech Republic 2Department of Forestry, Shaheed Benazir Bhutto University, Sheringal, Upper Dir, Khyber Pakhtunkhwa, Pakistan *Corresponding author: [email protected]; [email protected] Citation: Iqbal J. (2021): Impact of silvicultural system on natural regeneration in Western Himalayan moist temperate forests of Pakistan. J. For. Sci., 67: 101–112. Abstract: Site conditions (topography, aspect, moisture availability, humus thickness, light exposure, and grazing ac- tivities) play a vital role in the germination and regeneration process. The research was conducted in the Himalayan moist temperate forest. The research site was divided based on the silvicultural system (group selection system and single-tree selection system) into 148 plots and 150 plots, respectively. The group selection system was examined on the site of 2 ha which was clear-felled under a project in the 1980's. The present study examined the impact of silvi- cultural systems on regeneration. The frequency table was used, and relative frequency was calculated for the species and silvicultural system, density per m2 was also calculated. Diversity indices were calculated through taxa, dominance, Simpson’s index, Shannon index, evenness, equitability, and fisher alpha. Ten taxa were found in both silvicultural sys- tems, with individual repetition of 17 and 15 taxa, respectively. Group selection is more compact visibly as compared to the single-tree selection system. The single-tree selection system is more diversified in species composition, stand structure, moisture availability, and less humus availability. The study also highlights future predictions for the conser- vation of these forests, which are highly sensitive and a hotspot for wildlife and climate change phenomena. Silvicultural practices such as silvicultural system, cleaning, weeding, thinning operations are regularly practiced, which can reduce the negative impact on these productive forests. Keywords: diversity; mountain forest; stand structure; species composition; watershed The regeneration gap leads to the forest ecosys- woody vegetation are vegetative, viable seed bank, tem deterioration and degradation of forest stand dormant and persistent seed bank, fire-induced structure (Barnes et al. 1998). To investigate the life opening of cones, widely wind-dispersed seeds, cycle of forest stands, the regeneration process and locally dispersed seeds, and persistent juveniles factors influence the process needs to be identified (Grime 1988; Barnes et al. 1998). Seed production (Guo et al. 2003). Heterogeneity of forest stands in forest crops influences the rate of growth (diam- with species composition influences the rate of re- eter and height) which affects timber production generation (Chen et al. 2007). To maintain the eco- (Morris 1951; Tappeiner 1969). system of forests, the regeneration process needs to Natural regeneration in the high mountains is be properly managed through artificial and natural the only source of growing stock. Almost every regeneration (Kent, Coker 1992). In the naturally forest species is regenerated through seeds except regenerated forest ecosystem plants may die or re- some special broadleaved species (Yadava et al. cruit to the understorey when after the competi- 2017). On the other hand, vegetative reproduction tion they became a part of the overstorey (Barnes et (layering) of natural regeneration occurs more of- al. 1998). Regeneration methods that were found in ten than seed production in extreme site and cli- 101 Original Paper Journal of Forest Science, 67, 2021 (3): 101–112 https://doi.org/10.17221/124/2020-JFS matic conditions, such as in mountain areas (Va- Suitable growth conditions in these mountain cek, Hejcman 2012; Vacek et al. 2012; Bulušek et regions especially with uneven-aged structures al. 2016). Suitable ground and site conditions are are more suitable for sustainable management. required for the germination and establishment of According to the past practice in the temper- seedlings. Site conditions like topography, aspect, ate forests, a shelterwood system was adopted by moisture availability, humus thickness, light expo- classifying dry and moist regions. On the dry site, sure, and grazing activities play a vital role in the 10–14 m spacing or 51–75 seed bearers were left to germination process (Brewer et al. 2012; Vacek et provide sufficient seeds to the site, whereas on the al. 2017a; Gallo et al. 2020). Forest stand structure moist site 9 m spacing was observed or 123 moth- and density also affect natural regeneration by al- er trees stood there as seed factory (Champion et lowing the required light and availability of enough al. 1965 b). Supplementary artificial regeneration seed for germination (Rocha et al. 2016; Splawin- practices were also observed if there was a bad seed ski et al. 2016). Soil depth and decomposed humus season or any other natural hazards that were ob- with more nutrients are prone to be ideal space for served in the areas (de Carvalho et al. 2017). regeneration. The temperature in the mountainous The present study investigated the diversity in- regions fluctuates during the day (high) and partic- dex under different silvicultural systems, i.e. group ularly at night time (low) (Chakrabarti 2016). Natu- selection system (GSS) and single-tree selection ral regeneration is threatened by many natural and system (STSS) in the Himalayan region. The diver- anthropogenic factors. Natural factors that influ- sity index will assist forest managers and conserva- ence natural regeneration are heavy wind, erosion, tionists towards the sustainability and composition heavy rainfall, animals, natural fire, windthrow, of the forest stand. That can help climate change, air pollution load, and torrents (Vacek et al. 2014, reducing emissions from deforestation and forest 2017a, b, 2019; Tinya et al. 2019). Whereas graz- degradation (REDD+), and productivity compo- ing practices, tree harvesting activities, roads, and nents and aspects for model development through trails are the most important anthropogenic fac- the best harvesting system. tors which affect the regeneration process in high mountains (dos Santos et al. 2019; Maltoni et al. MATERIAL AND METHODS 2019; Rezende, Vieira 2019). Most of the forests have mixed species composi- Study site. The Western Himalayan moist tem- tion and also variation in structure in the mountain perate forest of Pakistan was examined for regen- region (Pignataro et al. 2017; Dănescu et al. 2018). eration under the silvicultural system. Two main Shade-tolerant and light-demanding species are silvicultural systems were recorded as GSS and common during the early stage of their life. Good STSS. The group selection system was examined seed years also influence the rate of regeneration, under a project in the 1980s, when a 2-ha area was and density and other parameters (height, crown, clear-felled, the present study examined its im- etc.) are also influenced by vegetation cover and pact on regeneration. The same site of STSS was microrelief in mountain forests (Vacek et al. 2015). also identified by help of the Kaghan Forest Divi- Climatic factors such as snow and heavy rainfall sion. The elevation of the site was between 2 100 also affect the favourable site for regeneration (Ives and 2 200 m a.s.l. (Figure 1). The total area of the 2004). Major and important tree species in the Himalayan moist temperate forest is 572 508 ha, study area which need consideration compared to i.e. 0.7% of the total forest cover of the country other plant species are Pinus wallichiana A.B. Jack- (Bukhari et al. 2012); the experimental area is 4 ha son that is highly shade-tolerant and mostly found (2 + 2) with quadrat sampling (quadrat size 1 m2), with Picea smithiana Wall. and Abies pindrow the sample size is limited due to the area of GSS. Royle. Cedrus deodara Roxb. is also dominated by The main species of the area are illustrated in Ta- Abies pindrow Royle between 1 800 and 2 400 m ble 1 along with the temperature and ecological above sea level, whereas they can be found from conditions. Floristic details of the region are shown 1 500 to 2 800 m a.s.l. Pinus wallichiana is a shade- in Table 2. Simpson’s index (1-D) and Shannon (H) tolerant species along with Cedrus deodara and index were calculated as 0.59 and 1.08, respectively, Picea smithiana, whereas Abies pindrow can grow in the group selection system, and 0.61 and 1.24 in under all other species (Champion et al. 1965a, b). the single-tree selection system. 102 Journal of Forest Science, 67, 2021 (3): 101–112 Original Paper https://doi.org/10.17221/124/2020-JFS Western Himalayan moist temperate forests in Pakistan Figure 1. Description and situation of the study area in Western Himalaya (ArcGIS 10.8.1 Academic) Data collection. The number of individuals The frequency Table was used in MS Excel and (seedlings and saplings) was counted in a quadrat relative frequency was calculated for the species and for specific plant species mentioned in Table 1. The silvicultural system, density per m2 was also calcu- sites with two different silvicultural systems (GSS lated by density. Diversity indices were calculated and STSS) were selected to examine and collect through taxa (S), dominance (1-Simpson index), the data. Data were collected using a 1 m2 quad- Simpson’s index (1-dominance), Shannon index (H), rat, measuring tape, Garmin GPS (eTrex 20x, 2015, evenness (e), equitability (EH) and Fisher's alpha (α) USA) was used for coordinate and elevation re- were calculated using the PAST software (Fisher et cords. Statistical packages PAST (version 3, 2013) al. 1943; Magurran 1988; Roth et al. 1994; Rosen- and MS Excel (Office 365, 2019) were used for the zweig 1995; Begon et al.