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Why large trees in urban areas are removed

Tree Ordinances have been successful at tree banking and tree planting, but it is rare they prevent the removal of existing trees on lots being developed or redeveloped in desirable urban areas. The reason, the perceived value of the land exceeds the value of the tree.

Trees require their roots, and in poor urban soils those roots can take up large swaths of land, often referred to as the critical root zone. The science dictates that removing more than one-third of the root zone can put trees into drought conditions since there are less absorbing roots to give water to the trees. Trees like us are mostly water, and when you restrict water they often die, although most often that decline can be over five to seven years.

Most large urban trees reside in older residential areas. These trees grow up mostly undisturbed in a front, back, or side yard for fifty years or more. The lots are often less than a quarter of an acre and run from $200-500K. The lot is attractive for development and/or rennovations due to its intown location combined with an existing home that is affordable due to its age and size. To maximize profit, the builder wants to build the most expensive home to fit on the lot. The homeowner doing a renovation wants a larger home. Lets say when the new home is completed it will sell for 800K allowing developer to recover their costs and some profit and the homeowner to gain some value. The problem is that the critical root zone of the existing tree on the lot could take up to 50% of the buildable area. Unless the penalty to remove it exceeds the return on the property, that tree is coming down. In the scenario presented that would require a penalty of around $100K to not make it economically feasible to remove that tree.

As a result of this difficultly, tree ordinances do not usually require saving existing trees or do not give a high enough penalty to protect them but instead encourage replanting and/or tree banking (recompense). In my next blog I will discuss the economics of tree banking and replanting.

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  • It might help if tree planting and banking were not the only options. Double credit should be given to existing trees. Given that a healthy existing tree will double credit is a small incentive to give for a tree that will more than double the canopy of a replant compared to a replant for most its life. Moreover when it does die, it will provide better spot for a new tree as its ecosystem will remain in tact. Last more Also, I would like to see more emphasis on working around trees via tree prescriptions by certified arborist (e.g. building on piers, mulching, root pruning, watering, etc.) by requiring mitigation before recompense via tree banking or tree replanting.  Mitigation could be capped at 5% of the cost of the project. From my experience very effective mitigation can be placed for less than $20K.

  • I've been working a bit with a city's landscaping ordinance (I can't say where) and the following articles struck me in regards to this topic:

    "(c) The responsible party [developer] shall contribute to the city a
    cash payment equal to one hundred (100) percent of an
    estimate prepared by a registered professional landscape
    architect or arborist, of the cost of the trees required by this

    (d) The city official shall determine annually the
    required per tree in-lieu cash payment amount. Such amount
    shall not exceed two hundred dollars ($200.00) per tree with
    annual CPI inflation adjustments commencing in 2001. Any
    in-lieu cash contribution required shall be limited to a
    maximum of ten (10) trees per site."

    Similar to the city discussed in Karen's post, this ordinance has a provision for in-lieu payments instead of planting or preservation, but the maximum value the city can charge per tree is $200! A decent size caliper ball and burlap tree from Lowes costs at least half of that, and provides very little ecosystem value.

    I'm hoping I'm reading this wrong, so please let me know if that appears to be the case. 

  • I should have mentioned in my post that this work is specific to the metro area of Atlanta, GA, as I know there are American Grove members all of the country (and world?).

  • This has always been a frustration of mine. I work in a planning department as a natural resources person after being in urban forestry for 18 years. Living in an area where trees are scarce you would think people would place more value on them but the almighty development dollar reigns supreme. Our ordinance related to tree preservation is shown below. As you can see existing trees do not get much credit, so its quite easy for a developer to remove and "replace". Most often they use the cash-in-lieu option because they couldn't actually fit the replacement quantities on lot.

    A number of years ago I was successful in having a full environmental value analysis done on a project that was removing a substantial grove of trees. This result in a substantial cash-in-lieu payment but still, as Neil noted, the small trees that were replanted do not have the same impact as the mature trees.

    Removal and replacement of landscaping.

    (1) Existing healthy trees and shrubs shall be preserved and incorporated into the overall site and landscape design to the maximum extent practicable. Existing trees may be credited toward minimum tree planting requirements as follows:

    a. Existing healthy trees may be credited toward tree planting requirements of this Section according to the Tree Credit/Debit Table in Table 18.44-6. Tree credits shall be given as long as all other provisions and the intent of this Code are met. Fractional caliper measurements shall be attributed to the next lowest category.

    b. No credit shall be given for existing preserved trees which are:

    1. Not located on the actual development site;

    2. Not properly protected from damage during the construction process;

    3. Prohibited species under the caliper size of thirteen (13) inches measured four and one-half (4½) feet above the ground; or

    4. Dead, dying, diseased or infested with harmful insects.

    (2) All trees to be removed from a multi-family (more than four [4] units), institutional, commercial, industrial or mixed-use property, whether on-lot or in the right-of-way must be replaced on-lot or in the right-of-way, as appropriate, unless otherwise stated in this Chapter. Cash in lieu shall be paid to the City for trees to be removed that cannot be replaced on-lot or in the right-of-way due to site constraints or overcrowding of landscaping based on the Tree Credit/Debit Table in Table 18.44-6. Cash in lieu shall be determined by a cost estimate based on a schedule maintained by the Planning Division for labor and materials of trees meeting the minimum size requirements.

    Table 18.44-6: Tree Credit/Debit

    Caliper at 4½ Feet Above Ground

    Number of Tree Credits/Debits

    20+ inches

    equal to 4 trees

    13—19 inches

    equal to 3 trees

    8—12 inches

    equal to 2 trees

    2—7 inches

    equal to 1 tree

    Less than 2 inches

    equal to ½ tree

  • Though I hate to see just about any urban tree come down, I especially hate when large old trees fall victim to the chainsaw.  Adding insult to injury is the fact that the vast majority of these trees end up going to the chipper, when they could (and should) provide valuable lumber for local consumers, builders, wood workers, etc.  That being said, I found a great local shop that accepts (and seeks out) local raw timber that he then cuts into slabs, hardwood flooring, planks, lumber, etc.  Please put Eutree on your radar.  It's run by Sims Acuff and he's just barely OTP near I-20 and I-285.  See  He's looking to collaborate with local tree companies to help these felled trees live on in a useful way!  

  • Yes it would be interesting to have a planner address this. I will seek one out. Right now the default planning is replanting trees on land that is becoming scarcer and more expensive. The end effect might be trees on less desirable land and not equally distributed throughout an area. Intuitively, I do feel it is important that green infrastructure is evenly spread out but not sure what the appropriate or minimum amount should be or how that can be accomplished given the higher perceived values of the land.

  • I was told that every tree on a property added $500 dollars per tree of value to the real estate. I have seen some of these developments where there are alot of big houses and they look barren and naked without big trees. We have a strange set of values here. Also, $500 dollars seems ridiculously low, but  I love trees. They are priceless to me.

  • I'm not a planner, but seems like a difficult proposition mainly because of the high variation with property values. In a compromising resolution where penalties were increased some, but not enough to equalize in high property value areas, I could imagine a development areas with lower values having large trees and and larger, more affluent developments having only small trees.

    I guess the answer would be tying the penalty for tree removal to the value of the lot (as a percent of the target selling price).

    It is an interesting dilemma especially when considered over time, when, in theory land for development is becoming more scarce so prices are continually rising.  

    Any planners out there have experience with this. 

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