Environmental Criteria Manual - 2021 3rd Quarter Rule Changes

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Consultation has concluded

The comment period ended on April 25, 2021. Questions and answers for feedback received during the engagement period can be found below and in the "documents" section to the right. For general questions, please email DSDEngagementUnit@austintexas.gov. Please continue to check the site for updates.


The Development Services Department (DSD) is proposing adoption of several amendments to the Environmental Criteria Manual (ECM) in the 3rd quarter of 2021. The amendments pertain to tree protection requirements and tree impacts and are intended to consolidate and clarify existing rules, and remove out of date graphics.

More detailed information about these changes is available in the Documents section on the right side of this page. Also included in this section are Frequently Asked Questions (FAQ), Important Links and Key Dates.

Please use the Question box below to send us your comments. We welcome all feedback about these proposed changes, how they may impact you, and how we can best design them to suit your needs. Your input will help DSD develop the final rule proposal.

The comment period ended on April 25, 2021. Questions and answers for feedback received during the engagement period can be found below and in the "documents" section to the right. For general questions, please email DSDEngagementUnit@austintexas.gov. Please continue to check the site for updates.


The Development Services Department (DSD) is proposing adoption of several amendments to the Environmental Criteria Manual (ECM) in the 3rd quarter of 2021. The amendments pertain to tree protection requirements and tree impacts and are intended to consolidate and clarify existing rules, and remove out of date graphics.

More detailed information about these changes is available in the Documents section on the right side of this page. Also included in this section are Frequently Asked Questions (FAQ), Important Links and Key Dates.

Please use the Question box below to send us your comments. We welcome all feedback about these proposed changes, how they may impact you, and how we can best design them to suit your needs. Your input will help DSD develop the final rule proposal.

CLOSED: This discussion has concluded.
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    Since the ECM already requires mulching of the critical root zone for areas not protected by fencing during construction it seems problematic to introduce "foot traffic" as an impact under 3.5.2 that could be construed to count against the 50% allowable for protected trees. Please also consider clarifying that these impacts are only considered only when in combination with construction activities.

    Ken Jones asked 3 months ago

    Thank you for your comment. We removed the specific reference to foot traffic and left “soil compaction” as the impact.

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    Hi, I have multiple comments regarding the below section. My comments will be made on a separate line following three asterisks (***) to distinguish from the current body of text: 2. Trunk Diameter. Generally, tree diameters are measured at 4-½ feet above grade (diameter at breast height). The measurement provides the most accurate dimension of the tree's crosssectional diameter. If the tree is on a slope, measure from the high side of the slope. Measure below unusual swells in the trunk (see Figure 3-1 in Appendix V of this manual) to avoid inaccurate measurements. Diameter shall be accurate to the half inch. Measurements falling between half inch increments should be rounded down. For example, an 18.9 inch tree should be recorded as an 18.5 inch tree. The diameter of a multi-trunk tree shall be determined by the total of the diameter of the largest trunk plus ½ the diameter of each additional trunk. All*** (TMS suggests a maximum of 6 largest/most substantial trunks to be utilized for consistency while not creating multi-stem specimens with huge CRZ's and minimal canopy mass) trunks with a diameter of one (1)*** (TMS suggests 4" as a minimum size. 1" is onerous, time-consuming, and will likely have individuals measuring many sucker sprouts or branches instead of true upright stems) inch or greater shall be included in this calculation, except in Hill Country Roadway Corridors as noted in Section 3.3.4. Identify multi-trunk trees within the tree inventory by listing the cumulative diameter with an M (multi-trunk). Identify each of the stem sizes when heritage*** (TMS suggests this be made a requirement for protected size trees as well) trees are listed. A multi-trunked tree is differentiated from individual trees growing from a common root stock if there is a visible connection between the trunks above ground. Trunks of different species should be considered separate trees, no matter how closely aligned.*** (TMS recommends adding a line "City arborist shall have the authority to reduce CRZ requirements for multi-stem trees if canopy mass is not reasonably proportionate to aggregate DBH measurement" - or something to that effect to allow staff discretion to reduce huge CRZ design constraints for relatively inconsequential canopies (as compared to single stem specimens). For Ashe juniper (Juniperus ashei), often referred to as cedar trees,*** (TMS recommends that ashe juniper be changed to "all non-heritage tree species - especially invasives and non-appendix F species - ") only single-trunk trees with diameters eight (8) inches and greater or multi-trunk specimens with at least one such sized trunk need be surveyed. The intent of this provision is to encourage the preservation of those mature cedars*** (trees) which provide valuable habitat for various species, while lessening the overall cost of the survey.

    Mark Mann asked 3 months ago

    Thank you for your feedback. These suggestions address a section of rules that is not being updated at this time, but we will save your feedback for future consideration.