Population pressure and agriculture and industry means that land is continually being cleared.
I urge anyone with the ability, plant a tree this year — maybe even a couple! You'll feel good about it, and it may well outlive you. The birds and insects and other life will be happy about it.
The best time to plant a tree is 10 years ago; the second best time is right now.
The number of trees (assuming it's correlated with the "green" area of the planet) has grown significantly in the last few decades[1].
Only a small part of the overall land of most countries is used by agriculture[2], normally less than 30%. Cultivated lands add up to 17,235,800sqkm, "other lands" add up to 131,701,100sqkm.
You seem extremely pessimist given the actual numbers.
Trees will plant themselves in most places if we give them the space and time to do so.
Small bits of land can be changed by man to be hospitable to trees and here planting by hand would be the only way. Usually tree planting efforts are for man, not nature.
There are some good activities where we can help by watering, weeding around seedlings and protecting from pests which goes beyond planting.
Tree planting feels and is good and engages ourselves with nature. Nature itself can do nature stuff without our help.
Population pressure and agriculture and industry means that land is continually being cleared.
I urge anyone with the ability, plant a tree this year — maybe even a couple! You'll feel good about it, and it may well outlive you. The birds and insects and other life will be happy about it.
The best time to plant a tree is 10 years ago; the second best time is right now.