Every state has a multitude of sources for information on tree identification & etc. Usually every state has at least one author that has written a book "trees of (your state)" Trees of Arkansas is one of the ones I use. Several field guides, including ones previously named, are also helpful. After you get into it it is very intriguing to try and identify a tree, since many times they look very different that photos in the books. Especially since they often hybridize!
When I started heating with wood again last year I was forced to remember many forgotten tree ID lessons and had to relearn finding Ash trees in the dead of winter. After awile you will begin to recognize the form of a certain tree and identify it with confidence.
In your state - Maryland I assume, try one or more of these:
DNR Forest Service
http://www.dnr.state.md.us/forests/
This is the website for the State of Maryland Department of Natural Resources Forest Service. It provides a wealth of information about Forestry and the Forest Resources in the State of Maryland.
Maryland Forests Association
http://www.mdforests.org/
The MFA web site is your tool to learn about issues concerning forest land, forest management, the forest community, and the forest products industry in Maryland. MFA was incorporated in 1976 and is a statewide, non profit, 501(c) (3) organization. Members are forest landowners, foresters and other natural resource professionals, hunt clubs and recreational groups, logging and trucking companies, the forest products industries, related businesses and individuals concerned about the wise-use of our forest resources. The mission of MFA is "to promote the maintenance of a healthy and productive forests land base so as to enhance the economic, environmental, and social well-being of all who live in Maryland."
Forestry Board Association
http://www.mdforest.sailorsite.net/
Maryland's Forest Conservancy District Boards have been working to perpetuate Maryland's forest resource for more than 50 years. As volunteer advocates for forestry, Forestry Board members focus their attention on Maryland's trees and forests...our renewable natural resource. The primary goals of the State Association of Forest Conservancy District Boards are to increase public awareness of environmental concerns and good forestry practices; to assure that board members stay informed of new forestry programs and practices; and to coordinate activities of Boards in promoting good forest management through the legislative process.
Garrett State Forest
http://www.dnr.state.md.us/publiclands/western/garrett.html
This is the website for the Garrett State Forest which contains a diversity of trees, abundant wildlife and beautiful scenery. In 1906 this forest was given to the state of Maryland and was the beginning of our present public lands system in the state of Maryland. Mountain forests, streams and valleys make up the 8,000 acres in Garrett State Forest in Garrett County.
Potomac State Forest
http://www.dnr.state.md.us/publiclands/western/potomacforest.html
This is the website for the Potomac State Forest. There are 11,461 acres situated between the towns of Oakland and Westernport and partially bordering the Potomac River, is reached from Maryland Routes 135 and 560. Mountain forests, streams and valleys make up nearly 12,000 acres in Potomac State Forest. The forest drains into the Potomac River Basin, and features the highest point in any Maryland state forest – Backbone Mountain, elevation 3,220 feet.
Savage River State Forest
http://www.dnr.state.md.us/publiclands/western/savageriver.html
This is the website for the Savage River State Forest. There are over 54,000 acres in the Savage River State Forest. It is the largest state forest in the Maryland state forest system. It preserves a strategic watershed in Garrett County. Trail maps are available at the forest office, for all trails, including the 10 miles of cross country ski trails. The forest is classified as a mixed hardwood forest. More than 12,000 acres of the forest has been designated as Wildlands.
An American Elm on our place. Several giants exist away from urban areas where they have been shielded from the blight.
Have fun learning to put names on them - then learn the latin names.
Frank.....