บทถอดความฉบับเต็มของ Soil is the Solution: Why Healthy Soil Matters for Trees

compaction and what that means for for trees and for our landscapes? 00:02:10.400 --> 00:02:11.120 Absolutely. 00:02:11.120 --> 00:02:17.680 Well, here at the seed campus, we have what I think is one of the largest compaction studies that I'm aware of. 00:02:17.680 --> 00:02:22.960 We have two acres of space dedicated where we have our native soil here. 00:02:22.960 --> 00:02:29.840 Uh, our campus was prior a golf course, so it's pretty good alluvial stuff, uh, good for growing grass and trees. 00:02:29.840 --> 00:02:35.919 And the other part of the research plots, we've scooped out 16 to 18 inches of the native soil. 00:02:35.919 --> 00:02:43.840 We've replaced it with subsoil from the building here as it was being built when they were excavating the basement. 00:02:43.840 --> 00:02:52.240 And that subsoil has been placed in those plots and then compacted to the level that you would see on a lot of uh typical construction sites. 00:02:52.240 --> 00:02:59.840 So it's low organic matter, low nutrient, uh pretty stony and uh pretty pretty hard. 00:02:59.840 --> 00:03:08.240 Uh to those plots, we've added different soil amendments uh so we can see some of the practices that we advocate here for at Davey. 00:03:08.240 --> 00:03:21.039 And this spring we planted 1,600 bare root trees of five different species into those, and we'll be looking uh at how those trees grow and the soil changes over the next uh many years, hopefully. 00:03:21.360 --> 00:03:24.159 What's an example of how you would change some of the soil? 00:03:24.560 --> 00:03:37.599 Sure, we've done some different amendments where what we would call soil renovation, where we've added compost and biochar and done some decompacting to uh fluff up the soil and get some more pore space in there. 00:03:37.599 --> 00:03:51.120 We've done things like vertical mulching, that is where we in targeted areas go down uh up to three feet and backfill with biochar, but that's just kind of punching holes through the hard spots of the soil. 00:03:51.120 --> 00:04:11.120 We've done uh applications of just compost or biochar mulch on the surface, some kind of typical fertilization, and we also have uh unamended controls so we can see if we did the do-nothing approach, what that looks like for those different uh the compacted and the uncompacted soils. 00:04:11.439 --> 00:04:15.120 How long has this research been going on at Seed Campus? 00:04:15.680 --> 00:04:21.920 Well, the initial plots were developed uh a couple of years back uh working with Dr. 00:04:21.920 --> 00:04:23.759 Chris Fields Johnson on that. 00:04:23.759 --> 00:04:26.560 The trees went in in the spring of 2026. 00:04:26.560 --> 00:04:29.279 So this is really part of our establishment phase. 00:04:29.279 --> 00:04:41.600 We need to get those trees growing to be able to use them as reporters for how the soil conditions are and what are different uh amendment or remediation practices, uh, how they're doing. 00:04:42.000 --> 00:04:47.839 How long do you think it will take until you know or or can you tell something already? 00:04:47.839 --> 00:04:51.120 Or I guess that's that's the question, huh? 00:04:51.680 --> 00:04:52.959 Yeah, it's pretty obvious. 00:04:52.959 --> 00:05:02.399 If anyone's uh been around a recent home development or a construction project, those trees and the compacted soils are struggling. 00:05:02.399 --> 00:05:07.040 They are small, they don't have a lot of leaves, pretty sickly looking. 00:05:07.040 --> 00:05:13.199 Uh so right now we really are seeing the major effects of the uncompacted and the compacted soils. 00:05:13.199 --> 00:05:18.160 The different remediation practices that we've tried, uh amendment practices. 00:05:18.160 --> 00:05:27.199 We're starting to see some differences there, but I think it'll take a couple of more years to to get over just seeing the major effects of compacted soil. 00:05:27.839 --> 00:05:51.839 Well, this is great research because uh there's so many places that we have to plant in these areas, and I think it still is not uh mystery is the wrong word, but I think it's there's a lot of different ways that people deal with that type of compaction, and when it comes to planting, and in my mind, I think almost every arborist does it a little bit different. 00:05:53.360 --> 00:05:58.480 Yeah, it's uh something that I experienced in my career as a landscape architect. 00:05:58.480 --> 00:06:13.040 You know, anytime we develop a site, we're driving equipment across it, we might be removing topsoil or organic matter because we don't want uh settlement in our structures or foundations or roads, utilities. 00:06:13.040 --> 00:06:20.480 And eventually the contractor is maybe putting back good soil and we're planting into it. 00:06:20.480 --> 00:06:27.120 Um, and arborists and other folks, homeowners, are going to be caring for those sites for years to come. 00:06:27.120 --> 00:06:31.759 It takes a lot of work to undo some of the things that we do to soil. 00:06:32.160 --> 00:06:32.480 Yeah. 00:06:32.480 --> 00:06:35.439 When does a contractor put good soil back on? 00:06:36.079 --> 00:06:37.120 That's a good question. 00:06:37.120 --> 00:06:38.959 I don't think I see it too often. 00:06:39.199 --> 00:06:56.800 No, you see it so often, uh in like just even in home construction where a farm field is stripped, uh, they bring in, you know, uh house after house after house and throw grass seed down, throw a couple trees in, and say good luck. 00:06:57.120 --> 00:06:58.000 Yep, exactly. 00:06:58.000 --> 00:07:01.040 As I say, that's the uh sod on clay mentality. 00:07:01.040 --> 00:07:02.879 It uh doesn't work so well. 00:07:02.879 --> 00:07:07.360 But yeah, I think there's a lot that can be gained from good soil care. 00:07:07.360 --> 00:07:12.560 I try to remind folks here that uh soil care is a form of plant health care. 00:07:12.560 --> 00:07:21.759 Nine times out of ten, I'd rather pay for good soil work and then plant smaller plants

uh and give them a real chance at success. 00:07:22.079 --> 00:07:27.279 That's such great advice, and that advice has been repeated over and over again. 00:07:27.279 --> 00:07:32.000 You know, spend twenty dollars for your planting hole for a five-dollar tree. 00:07:32.000 --> 00:07:34.560 That you know, that's a that's an old saying. 00:07:34.560 --> 00:07:44.079 And knowing though, exactly what should be put in that soil to me is is incredibly valuable. 00:07:44.399 --> 00:07:44.800 Right. 00:07:44.800 --> 00:07:56.079 Well, good organic matter, whether that's fresh compost, compost derived from leaves or um food waste, is a good start, manure products. 00:07:56.079 --> 00:07:58.639 Uh biochar certainly is another part of that. 00:07:58.639 --> 00:08:04.240 That gives us long-term soil drainage, long-term soil structure. 00:08:04.240 --> 00:08:12.160 Uh, that biochar is not degraded by microbes the way that compost is, so they're really serving different purposes in the soil. 00:08:12.160 --> 00:08:14.879 So it's a both and, not an either-or. 00:08:14.879 --> 00:08:21.279 And first and foremost, we got to decompact because it doesn't really matter what our soil amendments are. 00:08:21.279 --> 00:08:27.279 If the roots don't have pore space to grow through, they're not going to get to whatever we just added. 00:08:27.680 --> 00:08:35.840 Are there other types of compaction besides like big machinery coming through, or that's the main thing we're looking at? 00:08:35.840 --> 00:08:38.399 Because that's that's incredible compaction. 00:08:38.799 --> 00:08:41.679 Well, certainly any major equipment will do it. 00:08:41.679 --> 00:08:46.559 Uh, if you're parking cars on your lawn periodically, that can do it. 00:08:46.559 --> 00:08:54.480 If you're doing regular turf management, particularly if it's been wet, you have a greater chance of compacting soil. 00:08:54.480 --> 00:09:01.759 And I know I've got a spot in my yard where I walk around my garage that's probably compacted just from too much foot traffic. 00:09:01.759 --> 00:09:04.720 So it can really happen for a lot of reasons. 00:09:04.720 --> 00:09:07.679 Um just regular management. 00:09:07.919 --> 00:09:13.120 Is there something a homeowner can do if they have compact if they know they have compacted soil? 00:09:13.519 --> 00:09:14.240 Absolutely. 00:09:14.240 --> 00:09:19.759 Well, you know, certainly that's something an arborist uh like some of our Davey folks could help you with. 00:09:19.759 --> 00:09:22.559 You can do uh core arification. 00:09:22.559 --> 00:09:31.759 You've seen that probably where the um they pull small soil plugs out of the lawn and leave it there, uh kind of look like dog droppings sometimes. 00:09:31.759 --> 00:09:34.720 Those can get works back into the soil, that's good. 00:09:34.720 --> 00:09:44.080 If you can't actually get into the soil, even top dressing with uh compost and biochar is another way to eventually improve the soil. 00:09:44.080 --> 00:09:53.919 Uh doing it just on the surface is kind of what nature does when we return litter or leaves at the end of a season, but getting it into the soil is really the best way. 00:09:53.919 --> 00:10:02.879 Now, if you got big trees and tree roots, uh things you want to be a little more careful about, that's really something you want to call a specialist for and get us in there. 00:10:02.879 --> 00:10:08.399 We have certain tools that we can do that uh without harming the tree or tree roots. 00:10:08.799 --> 00:10:17.679 Is biochar something you would consider that is new in the industry, or is it something you've dealt with for a long, long time? 00:10:18.080 --> 00:10:20.720 Yeah, it's something that I've been around for a long time. 00:10:20.720 --> 00:10:29.039 Uh in my graduate career, one of the international leading researchers of biochar was doing some of the work at the university I studied at. 00:10:29.039 --> 00:10:32.559 Uh, so I've been around biochar long before Davey. 00:10:32.559 --> 00:10:42.879 Biochar has a longer uh track record in the agriculture space, you know, where you're looking at crop yields and have some pretty definitive ways to look at that. 00:10:42.879 --> 00:10:48.000 Uh biochar in the I'll say green or landscape industry, that's newer. 00:10:48.000 --> 00:10:49.600 I think there's a lot of interest. 00:10:49.600 --> 00:10:55.919 There's also a lot of questions about what it is, what it isn't, what it can be, what it's not, what it does. 00:10:55.919 --> 00:11:02.080 Uh, and that's all some things we are uh working on and incorporating in our work here at Davey. 00:11:02.320 --> 00:11:10.240 When you look at those research plots, could do you have a guess ahead of time, or do you have to to just look at the data? 00:11:10.240 --> 00:11:24.799 Like when you set up the plots and you're like, you know, I got a feeling that when I put compost and biochar in there, those trees are gonna go nuts, or do you have to just look at it from a science point, like I have to look at the data, I I can't do that. 00:11:25.120 --> 00:11:26.639 I try to do both. 00:11:26.639 --> 00:11:37.200 I mean, obviously, when we set it up, we pick some treatments that we know are gonna do poorly, or our typical practice because we need to have those to compare against. 00:11:37.200 --> 00:11:45.679 But we know that when we do decompaction and we add good organic matter, compost, and biochar, we're pretty sure we're gonna see good outcomes. 00:11:45.679 --> 00:11:49.600 Now, it's really nice when the data show that as well. 00:11:49.600 --> 00:11:53.519 That's what we'd like to lean into to make science-informed decisions. 00:11:54.080 --> 00:12:03.440 But I I mean, because you're using science, it could be where you look at one of those plots and say, Well, you don't need quite that much compost to biochar. 00:12:03.440 --> 00:12:04.639 Look at how this tree's doing. 00:12:04.639 --> 00:12:05.759 I mean, I that's a surprise. 00:12:05.759

--> 00:12:06.159 Exactly. 00:12:06.159 --> 00:12:07.519 That's a surprise. 00:12:08.240 --> 00:12:11.120 It is, and science will surprise you all the time. 00:12:11.120 --> 00:12:14.399 Biology doesn't always behave the way that we think it should. 00:12:14.399 --> 00:12:23.200 But you know, having the data to do it uh helps us inform our clients and helps our clients make good decisions, which is why we do it. 00:12:23.519 --> 00:12:28.559 Well, by what you were saying, you've had an interesting journey to what you're doing now. 00:12:28.559 --> 00:12:32.480 Tell me a little bit about it, how you ended up, where you ended up. 00:12:32.799 --> 00:12:33.759 Yeah, I have. 00:12:33.759 --> 00:12:41.120 Um, I started my career in central Iowa uh as a uh an associate landscape architect. 00:12:41.120 --> 00:12:48.879 Got really interested in why the planting designs uh we came up with didn't always work the way we thought they would. 00:12:48.879 --> 00:12:52.639 Turns out soil and soil compaction is a big part of that. 00:12:52.639 --> 00:13:01.039 Went through uh to a master's and a PhD in soil ecology, looking at how land use changed in Baltimore County, Maryland. 00:13:01.039 --> 00:13:07.279 When you take forests and farms and make those into residential spaces, how does the soil change? 00:13:07.279 --> 00:13:24.480 Ended up back in Iowa, uh in the Department of Horticulture at Iowa State University, teaching plant materials, uh install management, a lot of the kinds of things uh that I would do in in horticulture or as a landscape architect. 00:13:24.480 --> 00:13:28.240 Ended up back in practice and finally here at Davey. 00:13:28.240 --> 00:13:32.559 So it's uh been through through practice and through research. 00:13:32.559 --> 00:13:34.480 So I've got skills on both sides. 00:13:34.720 --> 00:13:36.000 Oh, that's awesome. 00:13:36.000 --> 00:13:45.440 How how many different areas are there where the research is happening that you set up like specific types of soil? 00:13:46.080 --> 00:14:11.120 Yeah, so uh we have one large uh two-acre research plot here where we're doing the study that I described, but we do uh work on soils all over um and are trying to figure out ways that we can embed research into like some of our Davey resource group projects or other um other right projects we do for our clients. 00:14:11.440 --> 00:14:16.799 When we're talking about soil compaction, what should we be looking for on our landscapes? 00:14:16.799 --> 00:14:21.600 Now, in my case, I have an arborist from Davey comes every six months. 00:14:21.600 --> 00:14:23.919 He's looking for that sort of thing. 00:14:23.919 --> 00:14:27.840 And you should have somebody come at least once a year out there. 00:14:27.840 --> 00:14:30.799 But we know everybody doesn't do that. 00:14:30.799 --> 00:14:34.320 What are some signs that the soil is compacted? 00:14:34.960 --> 00:14:36.559 Yeah, that's a great question. 00:14:36.559 --> 00:14:41.360 Uh, I think one of the easiest things we can do is notice how water moves. 00:14:41.360 --> 00:14:51.200 If it is standing or pooling on the surface of your soil, uh, you may have some compaction because the water can't infiltrate or move down into the soil. 00:14:51.200 --> 00:14:56.480 You might also notice some patches of pretty bare turf, thin turf. 00:14:56.480 --> 00:15:03.440 And sometimes even some weeds, like broadleaf plantain, is another indicator of soil compaction. 00:15:03.440 --> 00:15:09.279 It does well and is more competitive with turf when you have soil compaction. 00:15:09.519 --> 00:15:11.600 What do you hope for your research? 00:15:12.080 --> 00:15:20.639 Well, I hope to be able to give our clients more evidence and reassurance that you know spending more on their soil is really good for their plants. 00:15:20.639 --> 00:15:27.200 You know, a lot of times we get called there because the plant isn't doing well, and that may come right back to the soil. 00:15:27.200 --> 00:15:35.279 But sometimes that's a hard decision to make for our clients, and I hope this data will help them make those decisions with greater confidence. 00:15:35.519 --> 00:15:40.480 Well, Grant, as we always say in the Talking Trees podcast, soil is the solution, right? 00:15:40.720 --> 00:15:41.279 That's right. 00:15:41.279 --> 00:15:44.080 Trees are the answer, and soil is the solution. 00:15:44.399 --> 00:15:48.480 When you get those stickers, when they finally print those, I need some of those. 00:15:48.879 --> 00:15:49.519 I do too. 00:15:49.519 --> 00:15:50.720 I'm looking forward to it. 00:15:50.960 --> 00:15:53.279 All right, Grant, thanks so much for the information. 00:15:53.279 --> 00:15:55.200 Good stuff, and keep up the good work. 00:15:55.200 --> 00:15:57.759 Uh, I can't wait to hear about the results. 00:15:57.759 --> 00:15:59.360 We'll we'll talk again. 00:15:59.360 --> 00:16:00.159 Uh when? 00:16:00.159 --> 00:16:03.120 When when should we talk again about these results? 00:16:03.600 --> 00:16:09.279 Well, I expect to be able to say something a little different every year, but I'm looking forward to good stuff. 00:16:09.279 --> 00:16:09.679 Thanks. 00:16:10.159 --> 00:16:10.399 All right. 00:16:10.399 --> 00:16:11.519 Great to talk to you. 00:16:11.519 --> 00:16:12.240 Thank you. 00:16:12.240 --> 00:16:15.759 Well, Grant's work is truly groundbreaking. 00:16:15.759 --> 00:16:16.720 Get it? 00:16:16.720 --> 00:16:21.840 Now, tune in every Thursday to the Talking Trees Podcast from the Davey Tree Expert Company. 00:16:21.840 --> 00:16:23.200 I'm your host, Doug Oster. 00:16:23.200 --> 00:16:27.759 As always, I would love for you to subscribe to the podcast so you won't miss a show. 00:16:27.759 --> 00:16:29.440 And we'd love to hear from you. 00:16:29.440 --> 00:16:33.039 You can send us an email to podcasts at Davey.com. 00:16:33.039 --> 00:16:38.480 That's P-O-D-C-A-S-T-S at d-a-v-e-y.com. 00:16:38.480 --> 00:16:43.279 You can also click the link at the end of our show notes to text us a fan mail message. 00:16:43.279 --> 00:16:46.639 Your ideas could be on an upcoming show. 00:16:46.639 --> 00:16:50.799 And as always, we'd like to remind you on the Talking Trees podcast. 00:16:50.799 --> 00:16:52.879 Trees are the answer. 00:16:52.879 --> 00:16:57.360 And for this podcast, soil is the solution.