an estimated height of 35 feet. the applicant's reasons given for removal were disruption to the sidewalk, sewer intrusion and overheadlines invasion. the sidewalk on wisconsin street is 15 feet wide which would allow for a significant basin enlargement. we're recommending a four by nine foot basin to reduce the number of roots that would need to be cut in order to repair the sidewalk and give tree roots more room, it makes them less likely to disrupt the sidewalk in the near future. they tend to take advantage of the space there. they're a bit opportunistic. to address the second issue of tree system in the sewer. we often hear complaints tree roots have invaded a sewer line but there's no evidence that tree roots will actually break and then invade a sewer line. however, if a sewer is already cracked and degraded, tree roots would certainly exploit

those breaks and break the line, tu of any species of tree not just for a tree with somewhat aggressive roots. i think it's important to not have degraded sewers out there whether or not there are tree roots involved and if the sewer was repaired, then -- and upgraded, then it would be very, very unlikely this tree or any future tree would get into that sewer line. since i'm on the sewer, i wanted to address a comment made in the brief that described the design flaw. and i would just note at the d.p.w. hearing where ms. kantor testified because her house was set back and down, the sewer had an unusual design to it. and i think it angled and was also higher than usual. if i'm remembering correctly. so i believe the hearing officer's reference to that design flaw was based on her testimony that it was an old sewer and an old house and because of the hill and where

the house was located, her sewer had some problems with the design. but again, i just want to emphasize if the sewer itself was not already degraded, there's no scientific evidence that shows tree roots can surround and impact a sewer line. there's evidence they will exploit an existing crack. ms. kantor's objections to our suggestion that the tree basin be expanded to allow for safe sidewalk repair and reduce the likelihood of another disruption in the future was weediness and garbage and dogs. and any tree basin has the potential to get weedy and garbage can get trapped in there and dogs can be attracted. there are things you can do within our guidelines to put up an edging treatment to help reduce the likelihood of the dogs but some basic maintenance is a requirement of having anything in front of your

house, including just a bare sidewalk with no trees. you can have weeds come up in the cracks and garbage. i also would submit that's not a real valid objection to opening up the sidewalk further. it is true that metrosidius excelsior do have a aggressive root system and cause root damage but provided many benefits. she notes she appreciates trees. we all know i routinely come before you to emphasize the oxygen and storm water benefits, carbon dioxide uptake and carbon sequestration and i will emphasize again mature trees provide many greater benefits than do small trees so we would be at a 26-year deficit if this tree were removed and another small tree were planted in its place. in this case, the wide sidewalk does allow for a significant basin expansion.

we could mine high the number of roots that would need be cut. again, we would hopefully reduce the likelihood of a future disruption or at least a near future disruption, and we would further the benefits of this mature, established tree. just one example based on the species and size the tree can intercept more than 1,100 gallons of storm water in one year and with san francisco's sewer system it's a significant benefit to the city. so we would urge you to uphold our denial, preserve this mature, established tree. while we're certainly sympathetic to the costs, there are many benefits the tree provides to the city. commissionter fung: ms. short? is this tree, a christmas tree, is it on your recommended list? >> we recommend it in very difficult site conditions because it can take a lot of wind and salt and fog. i probably would not recommend

it on a hill where you have good site conditions. president peterson: i'd like to hear more from you on the benefits of a mature tree. you said something about storm water but i didn't catch it all. >> sure. trees help slow down storm water, large drain events and also through their roots uptake storm water. expanding the basin around the tree would actually increase the storm water benefit of preserving this mature tree. now, a larger tree will take up more storm water than a smaller tree so the benefits that the city gets from having mature, established trees are far greater than younger, smaller, growing trees. in addition, the highest mortality rates for trees are during their first five years so every time we remove a healthy, established tree, we're increasing the likelihood we'll have successive small trees before they get established so that's another

small concern. commissioner garcia: ms. short, not to parse your words in your brief but in your brief or in the brief it's stated that the sewer is -- i can't remember the numbers, eight feet away from the tree and the tree, the breakup of the sidewalk only extends six feet so therefore, it's been concluded that whatever damage there is to the sewer pipe is not from the trees, it's a design problem, as you mentioned, having to do with angles and all that stuff. but in our papers, and i'm sure you read the same thing, the appellant states they photographed the pipe and there's absolutely roots in there. and i know you said that's not something that's caused by a tree but it's something a tree will avail itself of if there's damaged pipe. >> that's right. commissioner garcia: can you talk about the eight feet, six feet issue? >> sure. i think the main reason for the

conclusion of the findings in the director's order was to suggest that the tree exceeds the guidelines for distance away from the sewer. and therefore, any repairs that would need to be made to the sewer could be made without destabilizing the tree or requiring its removal. in some cases we have trees planted very close to the sewer and in order to trench down 10 feet, you simply can't make that repair and keep the tree intact. and then the six feet was indicating that's the primary path of travel for pedestrians on the sidewalk. so as long as we have six feet that's intact, we can expand tree basins to allow for the roots without negatively impacting the pedestrian access. so whenever we're looking at basin expansions, we have to look at the a.d.a. guidelines and ensure we have sufficient pedestrian access. so that note, i believe the intent of that note was to suggest even if we make an

oversight basin, we've got six clear feet that's not being significantly damaged by the tree so we would have an intact sidewalk there. commissioner garcia: and the other issue i have, and it's come up before, is that is anyone paying tangs to hearings that go on at the u.f. and d.p.w.? if they were considering putting in a tree, they would say no, i don't think this is a good idea, look at the problems these people are having, the fact that i might have underneath my property or near to my property a sewer that is invasible might make me say, i don't know if it is, i don't want to go through the expense of having a photographer go out and run his camera into there -- not a photographer, a plumber, run his camera and find out if i have vulnerable sewer lines so therefore i won't put in the tree because if i do the city won't allow me to do anything but go repair that, keep a tree that's going to be problematical that they no longer recommend because it

has invasive roots, how do you respond to that? how do you respond to that person? >> that is a difficult answer to give, but i think i would say if -- i don't think it's in the city's best interest or anyone's best interest to have degraded sewer lines. so the sewer should probably be replaced, if there was no tree at the site, the sewer should probably be replaced because it's full of cracks and we have sewage seeping into our ground and ground water system. so if everyone were to upgrade their sewer to meet the current guidelines for a cast iron sewer, we wouldn't see very many tree-sewer conflicts. so i think my response, although it is not a cheap response would be the sewer should be upgraded one way are another, and if you upgrade the sewer, then you no longer have this real worry about the tree. commissioner garcia: but if i don't have the problem right now, i'm not aware of it, i

might have decreased -- you know, water flow, whatever it is when the sewer is going in or coming out, you know, and i'm not really aware of the problem, i'd love to have a tree, i think it's ecologic will i had good to have a tree but i don't want to go to that additional expense of having my sewer line photographed, so therefore thank you but i think this time i'm not going to put in a tree, you know. >> i think that's a legitimate risk that we run with our policy to try to preserve mature trees. i think my only other comeback would be, we've lost the vast majority of our mature trees. some estimates have stated we have 1% of mature, established trees remaining in san francisco. so the bureau's perspective is it these trees are healthy and we can have a safe pedestrian environment and preserve these trees, we've got to get the next generation growing or we're behind the eight ball. commissioner garcia: i have

four trees on my property, by the way. vice president goh: do i have a follow upquestion? i don't know if it's appropriate but i've heard and it's come in my neighborhood, a list including, i think from the captain of our police district, that there was a scam, a video -- i'll video your sewer line, street tree scam. have you heard about this? >> i've heard of this as well and don't know it's legitimate but we heard someone was going around and offering to do that and offering to expedite their permitting to get the tree out. vice president goh: and showing the video that was allegedly of this sewer but not really anybody's, the same video was shown over and over. so, anyway. thank you.

>> ms. kantor? you also have seven minutes. >> i'm elizabeth kantor. and i own this house at 835 wisconsin street and i've had it since 1980. and in 1984, you know, with active neighborhood enthusiasm, we planted the meteosidius excelsior tree in front of the house. it didn't come along with any advice or any cautions or any information about what the maximum height of this tree would be. it has reached a stunning height and a huge size, and it was certainly the tree that was planted by the friends of the urban forest. i did not, unfortunately, research it or make any selection at that time.

and in early 2010 i was cited by the city for the sidewalk, many, many squares, including the curb, and then i got informed by pg&e they were topping the tree because of the invasion of the overhead wires and i thought to myself how many times we have had to rout out the sewer pipe of roots, lately the plumber has been telling me he's taking roots out. it just seems like such -- the most obvious and perfect solution to plant another tree in that place. of course my own expense. this tree is now 26 years old. you know, the next one, hopefully, will be there as long and trees, you know, mature and age over time and another one needs to come, i think, to this place at this time. the situation with the sewer is

it is an old clay pipe, it's an old house. the house was built low to the street and over the years all the newer houses are higher so that there's nothing -- there's no design flaw, it's just on a rather level pitch, and it's very deep under the sidewalk. and it's not cracked or broken, i don't believe. but where the cast iron from the building meets the clay, there's a little leakage at the juncture there but it's under the street. and so that's probably, according to the plumber who took the photos for me, and i was there watching him put the camera down, you know, i looked in his camera, he made me a videotape and gave it to me, so i don't think it was anybody else's sewer that he photographed and showed me because i was watching the camera go through. the roots grow in at the place where the water leaks out where the two pipes meet. i don't think that that pipe is

broken otherwise or leaking, cracked, you know, under the sidewalk. but roots do grow in regularly. so anyway, obviously denials at the hearing and permits to replace this tree and in the course of preparing this brief, i discovered this is a notoriously nasty tree. it has really aggressive roots and caused tremendous damage, i bet you the city has given a lot of permits out and it knows, also, of a lot of damage that's happened to the city's own pipes because of the roots of this tree which are known to lift entire pipes. no, they don't necessarily go into them but the roots are huge and they lift pipes. and i've learned this from ann arborist i spoke to and also a fellow named lars costello, a uc-davis consultant to san

francisco county on street trees and probably is known to ms. short. i quoted, you know, basically our communication in our email that he really feels -- he wished me good luck. i invited him here tonight in terms of participating in this appeal. i'm so sorry that the bureau of urban forestry isn't on my side and isn't helping me in terms of giving me information about those trees and this tree which, you know, in fact shouldn't have been planted. i wish that they could help advise citizens of san francisco about the safest, best trees to plant and warn us of those trees that are likely to disrupt our systems, even if they've been in there for some number of years, because maybe

there is something i could have done years ago to, you know, walled off these roots from growing into the sewer pipe. it is far enough away in terms of feet down below the street, i guess, to meet the city's requirements, but for a 35-foot tree, the roots are growing at least 35 feet away from the base of that tree, and, you know, it's a nice tree but i think it's really -- in terms of the safety the street and theon going -- the ongoing sidewalk situation and sewer situation, it's time for it to be replaced with another healthy, sustainable tree. it's done its job and provided lots of oxygen, taken up lots of carbon monoxide over the years and i think it's time for another tree to start growing into that. at 835 wisconsin street.

i would like to perhaps -- i don't know if -- get the city's numbers, how many permits -- how many trees of this nature have in fact caused damage? i left a request at the bureau of urban forestry because i can only leave voicemail, to ask if i could get some numbers, some information or data about in fact how much damage does the city know this tree has inflicted on sewer systems, many of those probably the city's own. so that's the other piece of this that i don't have the information yet for. and perhaps it's worth gathering that and coming back to you. president peterson: ms. kantor,

did you offer a specific tree of any diameter. >> in fact, i would love -- i want the city to tell me, could i ask them, what would be the very best tree, the safest one, i'll put in whatever size tree is most likely to succeed, and what's going to be most likely to live past its first difficult five years and what size would be best to put in? i mean, i am ready to be helped here. i'm not the expert. and i suggested -- it's called a tristiana -- tristianopsis -- it was in my original permit but i was advised by ann arborist it would be the safest. president peterson: thank you. thank you. is there any public comment on this item? if there is, please step forward. ok. seeing none, then ms. short,

you have three minutes of rebuttal if you care to use it. >> thank you, karla short, department of public works, bureau of urban forestry. i don't need my three minutes but if a permit is granted we would be very happy to work with ms. kantor and advise her on species and we do it every day when people come to us for permits to plant trees or remove trees. tristianopsis loritis is a good street tree. all trees are capable of damaging sidewalk and all trees are capable of exploiting cracks or leaks in sewer systems but that tree tends to be very well behaved and is a good option and we'd be happy to talk about other options. i'm sorry we did not -- i didn't actually get the message, i don't know who in my office may have gotten the message asking for this information. i did read it in the brief. we don't track specifically this type of information and we

would only be able to look at the data we have which would be based on tree removal, permit requests and then reasons given for that. but we don't dispute that mtrosidius ex-celsius causes sidewalk damage with aggressive roots and isn't one we recommend in many circumstances in san francisco and tend to reserve it for really harsh climate conditions which also have sandy soil so that helps a little bit. but i think from our perspective, really, the goal is to preserve the larger, mature trees because they provide more benefits to the city. commissioner hwang: ms. short, i'd like to hear replanting of more, not the baby trees but do you ever have replantings with more mature trees and is that an effective sort of alternative? >> we do. and generally, there is some

evidence that younger trees will establish more quickly than larger trees when -- and the larger the tree, the more root system you need to be able to transplant so your transplant success, particularly if you're digging up a tree can go down the larger it is because you're less likely to get the full root system. having said that, planting larger boxed trees that have been grown in containers has been successful and we will often require it at our hearings if there's a particularly large tree that's being removed and especially if there's a neighborhood concern that they're losing that benefit and that tree. so it is certainly possible to put in larger box sizes. they would require a little bit more additional water and care to ensure that they don't go into transplant shock. but when they are containerized and grown into those boxes, there's a much better success of planting than something that

might be dug up. and i think when people talk about those trees getting established more quickly, it's the concern that you've lost some of the root system. commissioner hwang: another question i had was if you were to put one of those in, would -- where it was described by the requestor there's this leak that is where the roots enter, would that be something that you would recommend be resolved should a new tree be planted anyway? >> certainly. sewers are not designed -- they're not supposed to be leaking so if there's a leak where the tree roots are getting in, then there's a crack the roots are getting in and should be looked at and try to be ficked to prevent any future damage, yeah. commissioner hwang: is that something that your department deals with at all as part of a -- i don't know, compromise or resolution to someone who wants a permit and got it depped, wants to put a new tree in so

it doesn't happen in the future but part of the problem is the sewage issue? i don't know how much -- what's your scope there? >> sure. we're bureau of urban forestry pretty limited to trees but the department of public works have a street and sewer crew that works with the p.n.c. my understanding is the owners are responsible to the sewer's cleanout and the city is responsible from there. so depending on where this leak is occurring, it might fall on the property owner's responsibility versus the city's responsibility to try to fix it. but if the board were to direct us, i would be very happy to identify who in our street and sewer repair to fry to work with the property owner. commissioner hwang: thank you. vice president goh: we know this tree is 26 years old because the requestor planted it. do we have a sense of the lifespan? >> you always ask me that.

and i always try to avoid answering. urban trees have different lifespans than do trees in their natural setting. and trees are living things so it's very hard to predict lifespan. there are certainly examples of this tree being much, much older than 26 years old. but -- vice president goh: but mitch, much older you mean 100 years or 30 or -- >> i mean 60. i would say fairly easily beyond that. vice president goh: thank you. commissionter fung: is it fair to say that your recommendation would be on a replacement tree would be at least a 36-inch box? >> yes. i think that would be -- we would love to see as big a possible replacement tree. commissionter fung: and the magnitude of cost for that? >> the cost goes substantially higher when you get to a 36-inch box because it usually requires either a small crane or a forklift to be planted.

but the cost of the tree itself is, you know, probably several hundred dollars more. and in some cases, you can get the tree delivered with a crane so if the site is prepared you don't spend that much more because they have to use the crane to offload the tree anyway. but the 24-inch box can essentially be planted by two strong people and so it's much less expensive when it's being hired out. and then beyond 36 you get even more expensive. vice president goh: what size square were you recommending this be increased to? >> we had marked out a four-foot by nine-foot square for the existing tree. president peterson: how does it compare to the boxes you just talked about needing cranes? >> in order to plant a 36-inch box tree you would need at

least a four by four foot basin in order to get the tree into the basin. vice president goh: that's the one that would require train cranes? >> yeah. vice president goh: and the expense of taking down a tree it size? >> i don't know if ms. kantor has gotten quotes but there's good access because it's right on the street but i think upwards of $500. vice president goh: that's very little compared to the crane and whatnot. ok. thank you. president peterson: ms. kantor, you have three minutes of rebuttal. >> i'm dr. kantor, f.y.i. but -- sorry. i'm sorry, but i actually put the amount of the price. i don't remember. i'm told it would be $925 by costello's tree service.

president peterson: to remove the tree? >> right, to remove the tree. and the larger, you know, imprint in the sidewalk, the larger sort of dirt square area, it's really a huge four by nine feet is tremendous, like having a dirt lawn in front of your house. i realize it is a relatively wide sidewalk but it just -- i immediately was -- you know, it also has the water cap on the sidewalk there within that four by nine feet that was, you know, marked off by the white paint that the u.f. representative put on the sidewalk. so it's just -- i really felt that this would -- would just create a very large kind of dirt lawn in front of the house but it would be unfortunate and

i'm hoping to keep the square around the tree a bit smaller. again, the meterociderus is aggressive and at this point fair i had -- it seems widely known to be quite damaging to infrastructure. the only thing i found online was information from the -- it's interesting because this is called a new zealand christmas tree, and the only root advice regarding the damage and advice clearly not to plant this tree by a local area was from auckland, new zealand and the picture of horrible, huge roots causing a lot of damage to the area where they're gro