Gum Production and its Sustainable Harvest from Forest: a Review

Abstract

India is enriched with dense and diverse forest; the biodiversity of the country is so high that makes it a mega biodiversity center out of the 17 centers (Rewatkar, 2020). The variability in the edaphic, climatic, and topologic across the country makes it a favorable habitat for the highly diversified plant species and other life forms (Champion et al., 1968). The average forest cover of the country is 7,12,249 sq km, (21.67% of the land area of India) (ISFR, 2019; Rintelen et al., 2017). Apart from providing other ecosystem services (like regulating the climate, nutrient cycling, etc.), the forest provides subsistence to a large section of the population of our country. Millions of tribal people earn their livelihood from the collection and marketing of NonTimber Forest Products (NTFPs). Particularly in developing countries like India, gums and resins provide a significant proportion of NTFPs (Sharma et al., 2016). Collections of gums and resins provide livelihoods to millions of Indian people living in or around forests. Gums and resins are planted exudations that result partly from natural phenomena and partly by injury by insects, animals, or human beings. Gums and resins are generally exuded by plants in liquid form and on exposure to the environment, it gets dry into translucent tears and remains attached to the bark of the stem or branch (Sinha et al., 2005). These gums are otherwise known as tree exudates. These exudates (gums) have a historical background of about 5000 years, these are the composition of long chains of polysaccharides having a high molecular weight (Kaur et al., 2009), these polysaccharides are mainly composed of monosaccharides like uronic acid and some protein and fibers (Reddy et al., 2011). The population of gum yielding plants is decreasing day by day along with the increase of demand for these nontimber forest products in different industries like paper, textile, gas, cosmetics, etc. (Saha et al., 2017; Choudhary et al., 2014). The main reason behind this is the large gap in production and requirement of these gums. The shrinkage in forest cover and unsustainable methods of harvest leading to the death of the plants is the major cause of a decrease in the production of gum. India has almost 7800 medicinal Drug-Manufacturing Units that annually utilize about 2000 tons of plant and plant-based products (Wakdikar, 2004), a good percentage of which are gums and resins. It is reported that sales of non-timber plant products have grown by nearly 25% in India during the past ten years (Coppen, 1995). These gum-resins have important medicinal properties. Several types of gum are used in Ayurvedic and Unani medicine systems for treating various diseases like fevers, cough, cold, sexual debilities, dysentery, etc. (Dhiman & Kumar, 2006). Nowadays gums are also used in paper, textile, and cosmetic industries due to their quality of emulsions ability, retain moisture and impart a smooth texture (Goldstein, 1954; Nussinovitch, 2009; Srivastava & Ray, 2015). Gums and resins are produced as a natural phenomenon in the plant parts in which the internal tissues are damaged through the process of gummosis, this leads to form gum cavities or canals, which exudes a polymer of carbohydrates called gum. (Shah et al., 1976) these cavities Natural Resins and Gums (NRGs) are the major NTFP of Indian Forest products. These NRGs have a highly significant role in the paper, textiles, cosmetics and medicinal (to cure fevers, cough, cold, sexual debilities, dysentery) industries. Due to the increasing demands of NTFPs, sales of such products have been increasing significantly day by day. Now India is one of the top NRGs importers of the world though it has mega diversity hot spots. Improper tapping practices affecting a lot to the gum yielding plants. A proper and Continuous manner of research is required on the different physical, chemical and biological factors affecting gum production in different gum yielding plants to increase the production of gums along with decrease the damages facing the plants.