## 1 Introduction  
Forest sustainability and certification emerged as crucial global issues following the Earth Summit in 1992, with an original focus on tropical forests that quickly broadened to temperate and boreal forests [1]. Today, several leading certification groups have a huge impact on millions of hectares of forestlands [2]. Forest sustainability will be a fundamental issue impacting world forests over the next few decades, creating many related problems that will need to be addressed [3]. As human population increases, so does the demand for food, fuel, lumber, and other forest products. Increased food supply usually comes from clearing forestland for crop production and grazing. These harvested forests are often not reforested and forest depletion occurs. This happened in ancient Greece and the Roman Empire, throughout Europe during the mid- to late-Middle Ages, in Central Asia and China during the early centuries of the Common Era, and in the United States in the mid- to late-nineteenth century as timber was cut from region to region across the country [4]. Forest depletion seems to follow the development of civilization. Today it is still a global problem, especially in the tropical rain forest regions and even some boreal forests [5]. Forest depletion causes both ecological and economic problems. The vanishing forests provided timber and other forest products that serve as a foundation of many economies, habitat that supported biological diversity, and functioned as regulators of global climate change [6]. Deforestation leads to soil erosion problems and changes in the hydrologic cycle (ground water). Soil erosion can impact vegetation and the rate of evaporation from a watershed; it can also lead to siltation and shallower river channels. Trees serve as a storehouse for carbon and the loss of forest can result in greenhouse gas emissions. Deforestation can even lead to animal and plant species extinction. Illegal logging and loss of forest cover even in countries with a strong forest industry economic sector can easily impact quality of life standards [7]. Forestry has a central underpinning of sustained yield [8], developed in eighteenth century Europe to ensure a steady supply of wood, fuel, game, and other forest products [9]. The owner of a castle might require his forest to generate annual revenue to support the estate, or a town might require a local forest to provide a steady supply of firewood. A timber famine could lead to social and economic disruptions, and forest regulation was developed to ensure growth, mortality, and harvest levels produced a steady flow from the forest. Sustained yield has been a hallmark of industrial and investment forest land management, guaranteeing a maximum even flow of timber and producing products that supported economic interests [10]. Over the past quarter century the concept of forest sustainability has evolved to consider non-economic interests and the forest as a naturally functioning ecosystem; ecosystem productivity maintenance depends on all of its components and natural processes [11]. The concept came to be called ecosystem management. Today, forest sustainability has a broad multifaceted context that embraces more than the functioning of an ecosystem; ecological, economic and social values are integrated to form the basis of sustainability [12]. Forest sustainability in the management of forest resources is supported by forest certification schemes that attest that specific standards are met. Forest certification is performance-based and is primarily concerned with current forest management practices and their immediate impact on the environment. It does track the forest products through the commercial chain, from the harvesting site to the final users (chain of custody), but does not explicitly measure the impact of a particular forest product on the environment over its lifetime. Life cycle assessment (LCA) is used to assess a product's environmental impact over an entire life cycle, from resource procurement to final disposition.