Replanting Eucalyptus as a sustainable solution for pulp industry: A review

Eucalyptus has emerged as a prominent raw material in the paper industry, with Eucalyptus globulus and Eucalyptus grandis being the most commonly used varieties. Its versatility has led to its widespread use in various paper products, including cigarette paper, napkins, white paperboard, and more. However, different eucalyptus species grown under varied conditions can influence morphology, chemical composition, pulping conditions, and paper quality. Hence, selecting the right species is crucial based on various indices, such as fibre diameter, holocellulose, lignin, and ash content. Replanting has been recognized as a natural approach to enhance freshwater availability and mitigate climate change, making it an essential strategy for sustainable eucalyptus production. This review examines 21 recent publications from diverse geographic locations, exploring the impact of replanting eucalyptus on pulp industries. The study highlights the significance of replanting eucalyptus as a sustainable solution for the pulp industry and discusses the ecological benefits, environmental considerations, and challenges associated with eucalyptus plantations. Through a comprehensive evaluation of previous research, this study aims to shed light on the optimal practices for replanting eucalyptus and its potential contributions to the thriving pulp industry.


Introduction
Eucalyptus is one of the most famous raw material in paper industries.There are a lot of varieties of eucalyptus used for making paper, but the most common are Eucalyptus globulus and Eucalyptus grandis [1].In the production of high-quality cigarette paper, napkins, white paperboard, toilet paper, security paper, copy paper, writing paper, and other types of paper, eucalyptus pulp is frequently utilized [2].
Due to variations in soil quality and ground water level, eucalyptus species grown under varied topological settings have different effects on the morphology, chemical composition, pulping conditions, and paper qualities.The following factors are used to choose which species of eucalyptus to plant: fibre diameters, hollo cellulose, lignin, ash, alcohol-benzene soluble, and pentosane contents; suitability for producing high-quality paper using various indices; and features of pulping and paper production [3].
The industry of pulp and paper stands as among the most extensive sectors globally.It is dominated by companies from East Asia, Northern Europe and North America.America Latin and Australia also have significant pulp and paper industries.It is anticipated that both China and India will emerge as major players in the market over the coming few years [4].

Subject selection
The first step is to choose a topic for discussion.The research will concentrate on the requirements and models for replanting eucalyptus with the goal to handle the impact of eucalyptus plantation as a raw material on pulp businesses.The theme was chosen to examine the method for evaluating eucalyptus nutrition requirements, the use of and how eucalyptus water and energy are used in replanting eucalyptus, and the environmental impact of replanting eucalyptus plantation.
2.1.1.Collect appropriate references.The second step is article collection.Articles are collected from various publications.Papers in this study are those that have been published within the last five years.
2.1.2.Articles selected based on their abstracts and research criteria.The next step is to choose documents from the collection.Reading the abstract and conclusion of the article is used to make the selection.From the 34 collected resources, 21 articles, a thesis, and a book are chosen according to the connections of the article's title and abstract to the study's objectives.

Analysis of the selected articles.
During the fourth phase, the chosen articles are scrutinized with respect to their introduction, methodology, results, discussion, and conclusions.Each section is meticulously reviewed as a framework for this comprehensive review article.

Evaluating and discussion.
Based on the findings of each study, articles from the fourth phase will be examined and discussed as a resource in resolving the goals of the study.

Results and discussion
Eucalyptus holds significant importance within the paper and pulp industry, being a prominent tree species widely cultivated in temperate regions [6].Having a total cultivated area of 16 to 19 million hectares and annual productivity ranging from 15 to 25 tons per hectare, it is a tree that grows quickly [7].South America is where more than 55% of the world's current eucalyptus crop is produced.The forestry sector in Chile uses 11.9 million m 3 of eucalyptus timber annually, with 53% going toward pulp manufacture [8].
Eucalyptus, the fastest-growing Myrtaceae species, is additionally recognized as the red iron tree, gum tree, and safeda.Eucalyptus is a native from Australia, where there are over 600 different varieties.It was introduced to India in the late 18 th century [9].The Myrtaceae family of trees includes the tall, evergreen Eucalyptus as its most commonly introduced species.With over 500 tree species within the Eucalyptus genus, it has become the most extensively cultivated genus globally.Eucalyptus is predominantly produced in Brazil (covering 3.7 million hectares), India (occupying 2.5 million hectares), and China (spanning 170 million hectares) [8].
More than 20 million hm 2 of eucalyptus trees have been planted worldwide, accounting for 33% of all plantations.Eucalyptus uses a lot of water and over time decreases soil fertility.This could have an impact on the productivity of the land and the quality of the nearby water.By keeping the leftovers from logging, soil fertility can be preserved.When the residues are absorbed back into the soil, the abundance of organic materials in them may aid increase eucalyptus output [10].
The majority of eucalypt species exhibit both a high capacity for water absorption and a high level of tolerance to dry circumstances.The physiological and morphological parameters of the plant, such as root growth and variations in photosynthesis, stomatal conductance, transpiration rates, osmotic potential, and gas exchange, demonstrate this trait.Additionally, variations in the biochemistry of praline, total protein, and sugar concentrations were noted.Both the choice of prospective species and the performance of reforestation initiatives could benefit from extensive knowledge of eucalypt growth behavior, biochemical responses, ecophysiological, and sub specific variance under water stress conditions [11].
Eucalyptus production depends heavily on replanting, which has numerous advantages for the economy and the ecology.After harvesting, eucalyptus trees are replanted, creating a cycle of growth and use that is sustainable.The primary benefit of replanting is that it guarantees a constant supply of eucalyptus timber for numerous businesses.Due to its versatility in generating timber, pulp, essential oils, and other products, eucalyptus is highly prized.The demand for these priceless products could be met without destroying natural resources by replenishing the eucalyptus plantations [12].
There are some methods to plant eucalyptus, including direct seeding, which is scattering the tree's seeds directly into the place where they will be planted.seedlings grown in nurseries, When they reach an appropriate size, eucalyptus seedlings can be nurtured in nurseries and then transplanted into the field.Start by purchasing wholesome seedlings from an established nursery or starting your own from scratch.Root trimmings, Cuttings of the root system can be used to grow eucalyptus trees.Cut a section of the root system from a mature, healthy eucalyptus tree.Air filtration, Eucalyptus trees can be propagated using the air layering technique [13].
Eucalyptus biomass has significant nutrient accumulations, therefore it requires heavy fertilizer applications-primarily potassium-to sustain high productivity levels.Nitrogen (N), potassium (K), phosphorus (P), magnesium (Mg), and calcium (Ca) are the essential elements most crucial for the growth and development of eucalyptus.The high production produced by commercial eucalyptus farms in Brazil is preserved by the use of solutions and fertilizers because the locations used to produce this forest species often have excessive acidity in the soil and inadequate nutrient levels to preserve the crop's productive potential.Phosphorus and potassium are among the nutrients that are most frequently administered in eucalyptus plantations, and their ability to increase output is dependent on the agro climatic conditions and plant age [14].
Drought is the most prevalent environmental condition affecting plant productivity and one that impacts plant growth and yield.Global climate change has increased the frequency of severe drought situations.While drought-sensitive eucalyptus clones often have poor uptake effectiveness, low efficiency in using nutrients for development of roots, and high use effectiveness for leaf creation, drought-tolerant eucalyptus clones usually have high uptake effectiveness and low nutritional use efficiency [11].
There are several benefits to eucalyptus plantations, including ecological and environmental benefits.On degraded hillsides and wastelands, eucalyptus contributes nutrients to the soil and stabilizes the topsoil by dropping leaves.In order to ensure sustainability of ownership of land in the case of a disagreement, farmers produce eucalyptus, which generates revenue for them and has positive socioeconomic effects.The most suitable tree for making pulp and energy from renewable sources for industrial uses is eucalyptus.Eucalyptus guarantees affordability and uniformity in the printing, writing, and tissue paper produced [15].But, near the plantation area, eucalyptus can also cause the development of black water, which kills fish.High temperatures and wet conditions accelerate the adhesion of eucalyptus litter and residue, which results in this water's dark color.The reaction between the elements in the residue and iron cations (Fe 2+) affects the water [16].
The demand for pulp and paper products is rising, placing more strain on the industry's alreadyscarce forest resources and driving a need for additional fiber sources.Various options such as annual plants, fast-growing tree species with potential, leftover biomass, and several other alternatives have been proposed as viable sources for producing pulp and paper [17,18].
Recycling fibers have received a lot of consideration from businesses in the pulp and paper sector.Although utilizing recycled fibers benefits the surroundings and the economics, these techniques call for the use of various components and various recycling cycles, which causes the fibers' inherent quality to decline due to their shorter fiber length.As a result, this may lead to higher fines and less readily drainable papers [19,20].
The residual biomass from the production of pulp and paper has garnered more interest recently as a viable alternative source for the processing of fibers made from cellulose in pulp businesses.The advantages of making fibers from leftover bioenergy in the same operation reduce the expense of transportation and logistics of supply.Thus, the fascinating raw material eucalyptus bark is suggested for the synthesis of fiber [19].Eucalyptus paper sheets have stronger mechanical qualities than merit paper sheets [21].Paper can undergo recycling up to 3.6 times, offering the potential to be repurposed multiple times.Paper production facilities have the opportunity to contribute to waste reduction by recycling used paper products for up to 3.6 cycles before the paper fibers degrade [22].

Conclusion
In order to preserve eucalyptus production, ensure a steady supply of important materials, advance environmental conservation, encourage rural development, and support sustainable economic growth, replanting is an essential technique.It is a crucial step in creating a robust, environmentally conscious eucalyptus sector for the benefit of the present and future generations.Eucalyptus replanting as a renewable resource has a considerable impact on the pulp industry.Eucalyptus trees are a great source of wood fibre for pulp manufacture since they are quickly growing and extremely productive.The pulp business assures a constant and sustainable supply of raw materials by replacing eucalyptus trees in well-managed plantations.Eucalyptus trees grow quickly, enabling relatively quick rotation cycles that give pulp mills a consistent supply of wood fibre.This leads to the creation of pulp that is of a high calibre because eucalyptus wood has advantageous traits like long fibres and a low lignin level.Eucalyptus plantations also ease the burden on wild forests, encouraging ethical and sustainable forestry methods.The industry has a clear positive impact on the economy by generating jobs in the forestry, logging, and wood-processing industries.Eucalyptus replanting also helps to sequester carbon, which is helpful in the fight against climate change.The approach promotes research and development spending, which improves the pulp industry's productivity and efficiency.The industry's long-term viability is ultimately ensured by replanting eucalyptus as a renewable resource, which also links it with ecologically friendly methods.