INTRODUCTION

At the start of 2018, it was estimated that the population of the world was approximately 7.5 billion, a 212% increase from just 50?years earlier. Annualized, this growth rate is on the order of 1.5% per year. This dramatic and continual increase continues to create problems and challenges for leaders, including those in the political, religious, industrial, and natural-resource-related arenas. The consumption of goods in many areas of the world is today growing at a rate greater than the rate of population increase. Population and economic growth worldwide has resulted in substantial increases in the consumption of food and of raw materials needed to provide shelter, fuel, paper, packaging, and durable and nondurable goods of all kinds. Higher economic standards bring better healthcare, nutrition, and longer lifespans. Feeding 7.5 billion people is a daunting task. It is humbling to think that at any given time, should farming cease, there is enough food in the world to last for only 40 days. Higher standards of living in North America lead to bigger houses which consume greater forest resources per capita.

The long-term availability of crude oil has been a focus of concern since the 1970s. Concerns were magnified in the 2003-2008 time frame, when the per barrel price tripled from approximately $35 to over $100. Since then it has declined but the potential for great variability remains. Energy consumption and allocation concerns are likely to grow in the decades ahead. In addition, the availability of non-energy raw materials will likely gain more attention going forward as consumption expands and as, in the case of nonrenewable minerals, supplies of the highest grades and most accessible ores diminish. The use of food as energy, such as the case of corn-based ethanol, remains an issue of great contention. Supplies of wood, a renewable resource, are likely to continue to expand, the result of a long-term trend of growth exceeding removals in natural forests and tree plantations. The drop in paper consumption associated with an electronic and "paperless" society feeds back to individual and corporate land owners in the form of reduced timber value. Conversely, concerns about forest amenities other than timber are likely to continue to adversely impact the availability of timber from natural forests.

As shown in Tables I.1 and I.2, wood is a major raw material globally and within the United States. Globally in 2015, almost as much wood was produced on a mass basis for industrial products (non-fuel) as steel. In the United States, more wood was used on a mass basis in 2015 than any other basic material, and more than all metals and all plastics combined. Yet in most high school and college curricula, wood receives minimal attention.

TABLE I.1. Annual world consumption of various raw materials, 2015.

Source: Data for wood from Food and Agriculture Organization of the United Nations (2015). Data for cement, steel and aluminum from USGS (2017). Data for plastics from Association of Plastics Manufacturers in Europe (2016).

TABLE I.2. Annual US consumption of various raw materials, 2015.

Source: Data for wood from Food and Agriculture Organization of the United Nations (2015). Data for cement, steel and aluminum from USGS (2017). Data for plastics from American Chemistry Council (2017).

The use of wood for energy is increasingly important. Wood has long been the principal source of energy for heating and cooking in less-developed countries. Worldwide, a little over half of all wood that is harvested is used for home heating and cooking, a reality that is revealed in the difference between the roundwood and industrial roundwood numbers in Table I.1; the remainder is used in manufacturing an array of wood products. In the United States, a much greater proportion of wood is used as a raw material for wood products manufacture, ultimately providing shelter for citizens. Moreover, in the United States about 85% of the wood consumed for energy is used in the forest industries; the other 15% is used for other heating needs, such as heating homes in rural areas. The extensive use of wood energy by the forest products industries indicates that these interests have already made the leap to green energy. Since the 1970s, forest industries have been increasing the utilization of wood residues to supply the energy required to manufacture wood products. Residues such as bark, sawdust, product trim, and pulping liquors can now be almost completely utilized. Currently, the primary wood products industries of the United States are about 60-70% energy self-sufficient, meaning that only 30-40% of the energy used for the manufacture of wood-based materials is purchased from energy providers or produced from fossil fuels. This is a very significant advantage of wood as compared with cement, steel, plastics, and aluminum. The use of wood for the production of commercial energy, particularly electricity, has grown with the desire for alternative energy. Current policies and "green power" mandates make it economically feasible to pelletize sawdust, other residuals, and small-diameter trees in the USA, ship the pellets across the Atlantic Ocean, and use them for electrical power generation in parts of Europe. In the future, wood is certain to play a larger role in production of electricity and may provide a source of fuels such as cellulosic ethanol, pyrolysis oil, torrified wood, and liquid hydrogen as well.

It should be apparent that wood is a vital and versatile raw material. In addition to the economic and energy benefits of wood production, trees enhance the esthetic and environmental character of every region. Managed forests hold the key to mitigating climate change while also meeting basic societal needs, in perpetuity. The renewability of forests and the assurance that with wise forest management a supply of wood will be available indefinitely favor the use of wood as a basic raw material.

The use of wood for heat and as a material for shelter, dyes, tannin, and containers dates back to the early days of human history. Historical transportation via wood boats and ships, warfare that included long bows and catapults, wood-handled farming implements, and so on have shaped human culture for thousands of years. But the use of industrial wood in significant volume goes back only about 150?years.

In colonial America, wood was the foundation on which society was built. Buildings and furniture, spinning wheels and looms, dishes and pails, wagons and carriages, dinghies and ships, bridges and sidewalks, railroad ties, plows and hay rakes, milling machinery and sawmills, and products of every kind and shape were made from wood. Wood was also a major fuel source, used for heating and cooking and as the principal fuel of industry. There remains much basis for the axiom "communities develop where forests grow."

As an early English colony, America was prized for its abundance of tall pine trees, from which ship masts could be fashioned. As the colonies gave way to rapidly expanding cities, and as populations expanded, wood abundance in many areas turned to scarcity as unrestrained wood use, combined with land clearing for agriculture, resulted in greatly diminished forests. But as wooden wagon trains carried homesteaders steadily westward, new forests were encountered and the clearing of forests continued. Wood for fencing of pastures alone required enormous volumes of timber, with some 3.2?million miles of such fencing estimated to have been in existence in the mid-1800s. Development of the steam engine led to the need for great quantities of additional wood - for steamboat fuel and for railroad ties and trestles - and provided a means of moving large volumes of wood and other materials to population centers.

One of the early drivers of inquiry into whether things might be done to increase the efficiency of wood use was the tendency of wood to rot. The huge volumes used for ships, marine pilings, fencing, ties, trestles, bridges, and telegraph line poles required replacement after only a few years of use owing to natural deterioration. As noted by MacCleery (1993), just replacing railroad ties on a sustained basis required from 15 to 20 million acres of forest land in 1900. Interest in finding a way to preserve wood to...