The question of whether there are more trees now than 100 years ago does not have a single, simple answer, as the global trend is split between significant regional losses and gains. The overall picture depends on where one looks, how one defines a “tree” or “forest,” and whether the focus is on the number of individual trees or the total volume of wood. Understanding the current state of the world’s forests requires examining these geographical and methodological differences.
The Global Answer
Globally, the planet has experienced a net loss of forest area over the last century, with losses far outweighing gains. Historical analysis shows that approximately half of the total forest loss since the last ice age occurred in the last 100 years, driven by conversion to agricultural land. The worldwide net loss of forest area between 2010 and 2020 was estimated at 4.7 million hectares per year.
The majority of this decline is concentrated in the tropics, particularly South America, Africa, and Southeast Asia. Tropical deforestation, the permanent conversion of forest to another land use, accounts for the majority of global forest loss, accounting for over 90 percent between 2000 and 2018.
This persistent loss means that the total forest area and wood biomass continue to shrink on a planetary scale. Although the annual rate of net forest loss has slowed compared to the peak in the 1980s, the world is still losing more forest than it is gaining. The scale of deforestation in tropical regions masks the positive changes occurring elsewhere.
The North American and European Context
In contrast to the global trend, many industrialized nations in North America and Europe have seen a substantial increase in forest cover and tree populations since the early 20th century. In the United States, forest cover has been steadily increasing since the 1940s, following a period of aggressive timber harvesting and land clearing that peaked earlier.
Many countries in Western Europe have experienced a “forest transition,” where centuries of deforestation reversed, leading to a significant expansion of woodlands. This increase often involved the natural re-establishment of trees on marginal farmland abandoned due to economic shifts. The United States, Russia, and China have recorded the largest absolute increases in tree cover.
This regional rebound makes the question of “more trees” complex, as the experience in developed nations runs counter to the net global decline. These forests are generally younger and less biodiverse than the old-growth forests they replaced, but their area and stem count have grown.
Key Mechanisms Driving Forest Change
The primary factors driving these divergent trends involve shifts in human land use, energy production, and technology. For forest expansion in North America and Europe, a critical mechanism was agricultural intensification, which uses advanced methods to increase farmland yield per acre.
This boost in productivity meant the same amount of food could be grown on less land, allowing marginal farmland to be abandoned. This land naturally reverted to forest, a process known as natural regeneration. Studies show that this intensification and reduced forest grazing strongly correlate with positive changes in forest area.
Another major driver was the shift from wood to coal and oil as primary energy sources during the Industrial Revolution. Wood was previously the dominant fuel, and its harvest caused widespread deforestation. Fossil fuels relieved pressure on forests, allowing them to recover once wood fuel demand decreased.
Conversely, the continued expansion of extensive, low-yield agriculture in tropical regions, such as cattle ranching, remains the dominant mechanism driving global forest loss.
How Scientists Measure Tree Populations
Accurately answering the question of tree population change requires complex methodologies, as “tree” or “forest” can be defined in multiple ways. Scientists use national forest inventories, satellite imagery, and remote sensing technology to track changes. Traditional inventories involve on-the-ground measurements of tree density, species, and wood volume, providing detailed but localized data.
Modern satellite data tracks tree cover, typically defined as woody vegetation with a canopy height of at least five meters. This data is crucial for global comparisons but can conflate natural forests with commercial tree plantations or agroforestry, which have different ecological values. An increase in tree cover may not equate to a gain in natural, biodiverse forest.
Scientists distinguish between the number of individual trees (stem count) and the total wood biomass (volume). A newly planted forest may increase the stem count with small, young trees. However, ecological health and carbon storage, tied to the biomass of large, old trees, may take many decades to recover. These nuances explain why studies sometimes report conflicting figures on global tree population trends.