It's surely true what Ed Baker says about trees that they may be the least permanent type of feature that can be used for golf and its strategies.
They grow, they die, break, change size and dimension at any time, and may effect the entire concept of a hole without warning, if they're central to it, and without much ability sometimes to replace or restore that concept or certainly not without exorbitant cost. The apparent cost of replacing the tree greenside right at Pebble's #18 is shocking as could be, to put it mildly, and one that is of concern not just in cost but as to its impact on the strategy of the hole!
So although somewhat temporary and worrisome they can be used in interesting ways, in my opinion. And certainly using them properly takes some thought and planning like anything else in golf architecture! Face it, a well planned and cared for tree can last for many generations.
Their type, size at maturity, placement due to this, certainly needs to be taken into consideration!--a fact that it's apparent was very little considered on golf courses in the last 50 years particularly!
And certainly trees can have a very important and benefical effect if used for a particular "look" or "style" on a golf course like the "parkland" style that very well may use them prevalently although they may never actually become part of the strategies or primary "concept" strategy of any golf hole!
It appears though, that there may still be a great deal to learn about the use of trees in actual and interesting golf hole strategies and the question very much remains and remains unanswered about what is logically or inherently wrong with using them in golf strategy or strategic and design principle, particularly since the modern game has been so much more tipped to the side of the aerial game!
The aerial game is a reality and the fact remains there is no golf feature to deal with up there except the occasional wind! The tree is simply the most logical feature to use this way!
The examples of features that could alternate for the effect of trees on the aerial game are very rare! The old railway sheds, since replaced, on the "Road hole" may be the best example and is proof of how rare features are that really do effect the aerial game in a real trajectory and distance sense!
It's OK to say that you just don't like trees in golf strategy but that only says just that--that you don't like them--and says very little about why they can't have a use to interest the player in things like "in the air" angles and height considerations of trajectory and distance and such--not to mention the far more basic strategic principle regarding strategic planning for future liabilities! In other words planning shots that may not have to deal with trees on that particular shot but the next one, or maybe the one after that!
This to me gets down to the best of all golf strategies where important strategic considerations are not related so much to the immediate problem (the immediate shot) at hand but some future one (as Behr says). In this way the real essence of whole hole strategies become far more interesting in a unified context and trees may have their best uses in this context!
It's interesting again to consider what Behr thought in this context:
"Hazards (and trees can be considered that--my own words) are not penal areas. Punishment is not the end that penalty serves. On the contrary, hazards are pressure areas acting upon the mind. They make a call upon intelligence. And intelligence, in terms of pastimes, may be defined as the skill of the mind to cope with experience. Therefore if a golf hole is to have form, its hazards ("features"-my own word) must so react upon one another as to create unity. And as a result of unity the mind of the player is projected into the future. Each stroke comprehends not only an immediate problem but a future problem as well. It follows that every hazard ("feature") of a hole, even the hazards that abut upon the green of a three shot hole, must be felt by the player at the tee. Thus the golfer, just as the player of games, is forced to assume immediate risks if he wishes to rid himself of future liabilities."
Max Behr (1926)