Nutritional products that can be collected from trees include fruits, nuts, seeds, leaves, and bark. Tree products have been an important part of diets for thousands of years, from early humans 26 fruits and nuts to the first cultivation of important trees, such as mango and apple.
The apple is one of the world’s most cultivated fruit trees, 27 over 7,000 different kinds in existence. Despite their great 28 , however, most domesticated apples can be traced back to a common ancestor, the wild apple of Central Asia, Malus sieversii. Apples have been grown for thousands of years in Asia and Europe, and 29 to North America by European colonists in the 17th century. Today, apples are 30 eaten the world over and form the basis for multi-million dollar industries. In 2005, at least 55 million tons of apples were grown worldwide, which generated a value of about $10 billion.
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