Question
Jim, When I purchased my home, I inherited 440 ankle-high SLLP trees, and now 3 years later some are nearing 20' high. I have seen a black almost charred look on some trees for the past two season, I treated for bugs the first year, and nothing last year, the blackened needles fell-off but the tree continued to grow new needles seemingly un-fettered.  What disease or pest causes this charred-look?  Second question is, some branches are really low to the ground, in what season can I prune them and what should I treat the open wound with?  Assuming they can be pruned. Last question, a few trees are leaning-over because of new growth at the top of the tree forming a "Y" seems like I should cut one of the "Y" branches off.  Glad to have experts out there like you.

Answer
This black is sooty mold. Sooty molds of pine trees commonly occur on all species of pine. These fungi are named for the black spots or crusts of fungal growth they form on pine needles, branches and stems. Soot molds rarely cause problems in the forest. In some cases, however, they can interfere with the proper growth of pine trees in the urban landscape and in commercial plantings.

Although a few sooty mold fungi grow on plant substances exuded by the leaves, most grow on the excrement of certain sucking insects. The most common insects associated with sooty mold infestations are aphids, scales, mealybugs, and whiteflies. These insects feed on the sugar-rich contents of the phloem of plants and excrete a substance called "honeydew" that is very high in sugar. Sooty molds live entirely on the excretions of the insects, and do not penetrate leaf or bark tissues. No direct injury to the plant results from the presence of these fungi. However, sooty molds may be indirectly detrimental to plants by excluding sunlight and interfering with photosynthesis in the leaves.

The insects sucking the juices from the pines can be controlled with insecticides BUT with this many trees and  their size I would not worry about the sooty mold. The trees sound like they are growing great and over time will out grow this problem.

The lower limbs can be pruned just make sure you leave more than 1/2 the crown foliage intact. Prune in the winter months this will keep down the wound of sap flow that may attract insects. Do not use a pruning paint on the wound the tree will seal the wound with sap and heal faster without the paint. Prune the limb back to the trunk leaving no stub and the tree will heal over the wound.

The leaning tree if not more than 45 degrees since they are young will straighten out by them selves. Do not prune the "Y' form the trees that have a fork in the upper part of the tree. This will damage the trees growth. This characteristic is genetic, some pines are forked and their off spring will also be forked. These trees will grow as well as the straight trees. In a timber type operation these forked trees are removed during the first thinning operation. Forked trees grow less limber than straight trees but they are just as healthy as the non forked trees. I would not worry about either the leaning or the forked trees.   

Overall I think the trees are growing great and seem healthy I would not be concerned about these trees. If you want some on the ground advice I would call the local office of your State Forestry agency and ask one of their Foresters to come take a look and advise you. This is a free service. Their local number should be in your local phone book.