Mortal, whose love for our umbrageous realms
Exceeds the love of all the race of men;
Whom we have loved; and for whom have spread
With welcome our innumerable arms
In other words, Cole claims that he has loved trees more than anyone else, and the trees have loved him back!
His friend Asher Brown Durand (1796-1886) was another tree lover - the collections of the New-York Historical Society included hundreds of drawings and paintings of trees by him. They have an excellent website with high quality images, easy to search. I'm particularly intrigued by the large and very beautiful tree drawings he made in the early 1860s, and which he never exhibited or sold.
A friend of Durand, quoted by John Durand in his biography of his father, has the artist express his motives like this:
What a relief it was to be able to stand for an hour before some fine tree, in direct sympathy with it! I had done so when a boy, on long summer days, and now, when a man, I had a higher appreciation of it than ever, and enjoyed it all the more - the great happiness of standing face to face with nature!
Illustration: Asher Brown Durand, Early Morning at Cold Spring (1850). Montclair Art Museum.