[CANUFNET] tree protection

Fri Jan 20 07:38:34 EST 2017

I agree with Ian on this one.
I’ve been using othophotos to plot out trees and am getting better accuracy and working faster than doing actual GPS work.  GPS works great for newly planted trees but for trees with big canopies, reception is often hard to get, especially if you’re aiming for sub-meter.  There’s always the GPS offset option to get better accuracy under canopies but it does take more time.  The thing I do like with orthophotos taken in the Fall, is when using GIS software, on bigger trees you can use the shade projected from the stem and see where the trunk is actually located.  Using the different ortho layers (different years), you can better confirm the correct position of the tree.  It’s not perfect but a good tool.
Thanks

Justin Poirier
Technologue en foresterie urbaine – Urban forestry technologist, ISA certified arborist
Service de la Culture, Loisirs et Vie Communautaire / Culture, Leisure and Community Life services
Ville de Dieppe - City of Dieppe
t 506.877.7836
justin.poirier at dieppe.ca<mailto:justin.poirier at dieppe.ca>
dieppe.ca<http://www.dieppe.ca/>

S’il vous plaît, pensez à l’environnement avant d’imprimer ce courriel
Please consider the environment before printing this email

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De : CANUFNET [mailto:canufnet-bounces at list.web.net] De la part de Ian Hanou via CANUFNET
Envoyé : 19 janvier 2017 18:51
À : Marie-Hélène Sauvé; Canadian Urban Forest Network
Objet : Re: [CANUFNET] tree protection

Here is my $.02 after a whole lot of time in urban forestry, GIS and inventory software:

 *   GPS is being used less and less in urban areas for data collection. Reasons: 1) with base map tiles (Google Maps, Bing Maps, etc.), the horizontal accuracy of the ortho photos is sub-meter (1-foot is common in the US). Unlike our cameras, each pixel has an x/y location, so when you "drop a point" (digitize a tree's location) in an online map, you're creating the x/y coordinate, replacing what GPS does (you use the "blinking blue dot" for navigation, not data collection), 2) you can use tablets and smartphones which are prolific and so much cheaper (and versatile/useful!) than $6,000 GPS units + GPS software, 3) most new tree inventory software are web/mobile-based and GPS is an optional way to collect the tree's location whereas digitizing the tree on an ortho photo is the primary method, and 4) these inventory software apps allow you to simply "drag" (move) a tree point, instantly updating the x/y coordinate, based on whichever base map you feel is most accurate (in horizontal / positional accuracy). Wait! There's #5 ... is super simple to zoom into a map and drop a pin in the middle of a tree using high-res base maps, unlike GPS units and differential correction, etc. Try it here, a free starter tool for basic tree inventory: https://pg-cloud.com/PlotterLITE/.
 *   In heavily wooded areas or where trees are close together, digitizing a point location is more challenging of course, but so is GPS in heavy canopy. There is no perfect answer, but there are techniques like tree tagging with physical tags to be able to do cohort studies, etc. This is more expensive, so choose the approach that works for your requirements and the site context.
 *   We're almost finished writing an article about cheaper GPS units that connect to web browser mapping applications via Bluetooth. There is a Bad Elf unit for $599 (US) that says it can produce 1-meter horizontal accuracy. I'd be happy to send that out when it's ready.
 *   I also wrote about some of this on our blog<http://www.treeplotter.com/single-post/2016/10/20/Base-map-tiles-accuracy-and-imagery-shifts-between-different-sources>.

hope this was useful ... cheers!

On Thu, Jan 19, 2017 at 3:08 PM, Marie-Hélène Sauvé via CANUFNET <canufnet at list.web.net<mailto:canufnet at list.web.net>> wrote:
Hi there,

Just to adjust something about GPS and urban forestry: there exists many
types of devices that are accurate enough (+/-10cm precision) to make a very
good distinction between two trees located nearby (and even the property -
if it's a public tree or not). Those devices are way more expensive than
those easy-to-use Garmin or other GPS device used traditionally in forestry.
Those high-level precision GPS are used by some consultants in the Greater
Montréal. So YES, it may be used and applied. The user has to know how to
use it properly though; GIS skills are required!

Cheers,

Marie-Hélène Sauvé

-----Message d'origine-----
De : CANUFNET [mailto:canufnet-bounces at list.web.net<mailto:canufnet-bounces at list.web.net>] De la part de via
CANUFNET
Envoyé : 19 janvier 2017 13:12
À : jd at dunster.ca<mailto:jd at dunster.ca>; Julian Dunster; Michael Richardson; Canadian Urban Forest
Network
Objet : Re: [CANUFNET] tree protection

Unfortunately GPS is not accurate enough to plot trees, especially when
landmarks that are accurately located by a surveyor aren't close by (i.e. a
forest or large natural area).  GPS's currently available don't have the
resolution to separate two trees that are 2 feet apart, or may be on the
other side of a property line with 100% accuracy.  A critical point. It's a
help but not the solution, yet.

CAD and GIS are great for plotting the data (we use both) but the locations
need to be accurate to start with. The days of drawing-in a dot by hand on a
site plan are gone.

Stephen Smith
ISA Certified Arborist, Urban Forester
Urban Forest Associates Inc.
-----Original Message-----
From: Julian Dunster via CANUFNET
Sent: Thursday, January 19, 2017 11:56 AM
To: Michael Richardson ; Canadian Urban Forest Network
Subject: Re: [CANUFNET] tree protection

Many of arborists in Britain regularly use GPS, GIS, and CAD routinely for
development projects. One of them developed special CAD software for the
purpose. The lack of its use in Canada almost certainly reflects a lack it
being taught in curricula, as part of professional practice. We still focus
on pruning, planting, fertilising and tree stuff, all of which is fine but
needs expanding to the 21st century to include effective use of technology.
Several of my colleagues in BC use CAD all the time. I use GPS and GIS.

We need to expand the horizon of what arboriculture and urban forestry might
/ should entail. At the same time we can also inform surveyors and
architects of we expect them to produce - such as CAD symbols for canopy
that are scaled to reality on the ground, not simply rubber stamped on a
plan, all at the same size (a pet peeve).

On Behalf of Dunster and Associates Environmental Consultants Ltd.

Dr. Julian A Dunster R.P.F., R.P.P.., M.C.I.P., ISA Certified Arborist, ASCA
Registered Consulting Arborist # 378, ISA Tree Risk Assessment Qualified BC
Wildlife Danger Tree Assessor Honourary Life Member ISA + PNWISA

North American distributor for Rinntech
www.dunster.ca<http://www.dunster.ca>

>
> Some interesting thoughts here.
>
> Those little dots; most arborists I know do not have the equipment or
> expertise to to locate trees with any precision, nor the GIS software
> to plot them.  If an arborist is using a plan created by a surveyor
> than surely the arborist must locate and plot not the tree, but the
> entire trunk diameter or root collar/trunk flare with the same
> accuracy and precision.
>
>
>
>

--
Ian S. Hanou | Plan-It Geo, LLC.
Owner & Director of Business Development
ianhanou at planitgeo.com<mailto:ianhanou at planitgeo.com>
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