There are many wonderful tree species in the world. Far too many to rate or designate as to which ones are “the best”. Because “the best” becomes relative to area, site and personal preference: “Beauty is in the eyes of the beholder.”
Unfortunately, it is not uncommon to hear someone refer to a tree as a “trash” or “weed’ tree, implying it has no value. Sometimes this is in reference to a native tree that grows prolifically but doesn’t necessarily have a long lifespan, such as some alders, Alnus spp, or the water birch, Betula occidentalis, both common in riparian areas. But ecologically, they perform important functions. In addition, they can be beautiful additions to a naturalized landscape.
Sometimes the reference is to a non-native species commonly planted in the past which has proven to be less than ideal in the present. The silver maple, Acer saccharinum, and Siberian elm, Ulmus pumila, are examples. But a tree suitable for Zone 2, as is the Siberian elm, has a place in difficult-to-grow climates. And frankly, it is not the tree’s fault when planted in an area with a milder climate where they grow rapidly, seed prolifically and are often, in my humble opinion, managed poorly. This is often the case with both the silver maple and the Siberian elm. Planted suitably and managed properly both of these species can be assets to a property.
Many people do not live in areas where a luxurious climate offers an abundant diversity of species from which to select. When your options are limited, then each and every tree has a place and purpose and can and should include both native and non-native species if we are to achieve recommended diversity for long-lived sustainable urban forests.
Some species have acquired a “bad rep” due to fast but weak growth, potentially invasive qualities in their introduced home, production of substances which have proven problematical to people with allergies and now appear on banned lists in some areas. These are, for the most part, justified for specific areas but these condemnations should not be construed as limiting criteria everywhere.
The box elder is a fast-growing tree in the maple family with a large native range here in North America. It is considered by many to be a “weed” tree. However, if you are in a challenging environment, this tough tree may be the perfect answer to a resilient shade tree.