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We all love trees in our built landscapes, but the odds are against their survival if we don’t follow a few simple rules. Although I’m not a horticulturist or urban forester, I’ve worked with people in those professions in the past and learned a lot from them. I’ve also attended lectures and webinars by renowned arboriculture expert, James Urban, from which I’ve gained valuable knowledge.

I’ve seen countless examples of trees that are improperly sited, planted, and/or maintained, which oftentimes has shortened their life span. Below I’ve listed some guidelines for design, installation, and maintenance that will increase the chances of your new trees thriving to a venerable old age, and keep existing trees healthy as well.

New Trees:

  • Shade trees such as Maples and Oaks should be spaced at least 35 feet on center for healthy crown (canopy) development.
  • Do not specify tree grates or guards. These will girdle (i.e. strangle) trees when their trunks outgrow the size of the grate hole or guard diameter. Better alternatives around the base of the tree are mulched areas, groundcover plantings, pavers on sand setting beds, or porous rubber surfacing, which the tree trunk can push away as it grows.
  • Avoid specifying staking and guying, since the guys are frequently never removed, girdling and killing the tree as it grows. A tree cannot survive if its supply of water and nutrients is completely cut off. (This action occurs in the cambium layer, just beneath the bark.) Trees do not need stakes and guys unless they are planted in extremely windy sites or have abnormally small root balls in comparison to the size of their canopy. In these cases, make absolutely sure that the stakes and especially the guys are removed after the first growing season.
  • Tree roots generally extend at least to the edge of the zone beneath the canopy of the tree, and often beyond that. Don’t limit the root zone to such a small area that the tree becomes stunted. Plan for its future growth where possible.
  • When the budget allows, invest in modular subgrade cells and structural soils to prevent soil compaction where trees are sited in sidewalks, plazas, and other hard-surfaced areas. These allow roots to grow sufficiently beneath paved sites, resulting in much healthier trees than those planted without these systems.
  • The planting hole should be at least twice the diameter of the root ball.
  • If roots are pot-bound (encircling the root ball), they should be unwound and extended out from the root ball as much as possible when planting.
  • The root ball should be set on firm soil so it the ball does not settle. The trunk flare, or collar, needs to be at least 3 inches above surrounding grade.
  • After the root ball is set in the hole, the areas around the root ball should be backfilled with un-amended native soil. Tamp soil in place by hand. Water heavily before mulching, and fill with more native soil where it has settled. Do not place any soil over the root ball.
  • Mulch should be about 3 inches thick, but no mulch should be placed within 6 inches of the trunk.
  • Trees should be watered at least once a week during drought periods for the first two years after installation. This means thoroughly soaking the root ball by hand, and not relying on sprinklers!

Existing Trees:

  • On construction sites, keep construction equipment and any other heavy objects away from the root zones of existing trees. I advise specifying/installing temporary fencing around the root zones for this purpose. Compaction of soil around roots will kill a tree.
  • Do not specify any grading within root zones of existing trees (neither cut nor fill). Cutting will destroy roots; filling will suffocate them.
  • Do not trench though a tree’s root zone, for installation of utilities or any other purpose. As mentioned earlier, this zone often extends beyond the tree’s canopy edge. The small feeder roots near the surface of the soil are just as important to the tree as its larger roots are. Cutting through any roots will often shorten the life of the tree.

All Trees (Old and New):

  • Do not “volcano mulch” around trees (piling mulch high around the trunk). This can lead to rot and decay of the buried part of the trunk, and result in a tree’s death. As noted earlier, mulch should only be about 3” thick, and should not be placed within 6” of the trunk.
  • Keep a mulch or plant bed around trees that are in an open lawn situation, instead of allowing grass to grow to the trunk. Turf adjacent to trees can be an invitation for overzealous weed trimming around the trunk, which can cut through the bark, particularly of young trees. If these cuts completely encircle the tree, this can result in girdling, leading to the tree’s death.
  • If you’re going to hire someone to prune your trees, be sure to hire a certified arborist for this job, not just anyone with a chain saw. Improper pruning can compromise a tree’s health.
  • Do not encircle a tree’s trunk and branches with strings of holiday lights, unless you plan to remove the lights after the winter season or holiday. If the lights are left in place indefinitely, the tree will be girdled as it tries to grow.

trees-2-straps
Death by tree ties
 
trees-3-grates
Trees outgrowing their grates and guards
 
Photo credits:
Top photo of large tree – Stefan Wernli (obtained from Wikimedia Commons)
All other photos – Alice Webb

On a chilly, windy Sunday back in late March, I walked the majority of the Rose Kennedy Greenway while visiting Boston. I found that most areas were devoid of visitors, except for the North End Parks and the southern-most tip at the Chinatown gate (which always seems to have activity). The two North End parcels (divided by a cross street) include a spacious steel pergola running along the east perimeter, facing a lawn and linear water play areas. I imagine that these spaces attract big crowds in summer, judging from the amount of use they got on the cold day I visited. The parks feel quite connected to the city, with views in all directions of downtown and north end buildings, as well as the iconic Zakim bridge. However, ample plantings and some grade separations help to segregate these spaces comfortably from the busy perimeter streets.
 
North End Parks 1
All the swinging benches in the pergolas were occupied at the time – unfortunately, I’ve heard that they’ve been removed due to maintenance/safety issues, and replaced with standard benches (which were there before).
 
North End Parks 2
 
North End Parks 3
Area with water play jets
 
North End Parks 4
 
North End Parks 5
 
Photos by Alice Webb

I finally got to visit the play area on the Common in Cambridge, Massachusetts – A superbly-designed space with hills, custom wooden structures, sand and water play areas, logs, plants, and other fun and unusual components. It includes many elements that help define a successful playground – one modeled on natural features that fosters imaginative, open-ended play. Although there weren’t many children there when I visited (likely due to cold weather and other plans on Easter Sunday), I could tell that the playground is well-used and loved, with sand tracked all over the place!

 

Cambridge Common Playground 1
A challenging wooden climber

 

Cambridge Common Playground 2
Sand play station

 

Cambridge Common Playground 3
Swings, plants, rocks, and a wheelchair-accessible merry-go-round

 

Cambridge Common Playground 4
Climbing net on a hillside

 

Cambridge Common Playground 5
A custom wooden structure, slide, and tunnel

 

Cambridge Common Playground 6
Water play station (too cold in March for the water to be turned on yet)

 

Cambridge Common Playground 7
One of several attractive custom wooden benches

 

Cambridge Common Playground 8
Custom wooden picnic table and seats

 

Cambridge Common Playground 9
Sculptural entry gate

 

Cambridge Common Playground 10
Logs provide a balance challenge

 

Cambridge Common Playground 11
Wooden “ship”

 

Cambridge Common Playground 12
Double slide embedded in a mound
 
Photos by Alice Webb

Red Butte Garden

I like to post photos of warmer seasons while we’re in the depths of winter, to remind us that spring is not very far ahead. Here are a few scenes from a lovely botanical garden on the edge of Salt Lake City, Utah, which I visited last June.

 

Red Butte Garden 1
Allium and falling water

 

Red Butte Garden 2
Four Seasons garden

 

Red Butte Garden 3
Herb garden

 

Red Butte Garden 4
Fragrance garden

 

Red Butte Garden 5
A roof garden with a view
 
Photos by Alice Webb

LDS center 1

While in search of interesting examples of landscape architecture in Salt Lake City last spring, I came across a building and site with an unusual juxtaposition of formal and naturalistic design. The LDS Conference Center includes two sides that were designed to represent a mountainside, dominated by a series of terraces with coniferous trees. The other two sides of this massive edifice, however, are quite formal in design, with a prominent tower from which a water cascade falls to the street level below. The roof landscape also features this peculiar blending of nature and structure. It’s almost as if vegetation were taking over the building from the east and north sides. Many parts of this design are quite attractive, but I’m not so sure that the scheme works as a whole.

 

LDS center 2
LDS Conference Center (view from south) – The vast and stark hardscapes of the roof and entry plaza contrast with the naturalistic planting design of the roof’s large meadow and trees.

 

LDS center 3
LDS Conference Center (view from northeast), showing the planted terraces

 

LDS center 4   LDS center 5
Formally-designed elements of the building and landscape include a tower with a water cascade that falls down to the street level, and reflecting pools on the roof.

 

LDS center 6
Up on the roof: One in a series of formal water features with a naturalistic landscape beyond

 

LDS center 7
Tower view on the roof

 

LDS center 8
The roof includes an expansive meadow with a view of the distant mountains

 

LDS center 9
Northeast corner of the building with trees on terraces, suggesting a mountainside
 
Aerial images obtained from Google Earth; all other photos by Alice Webb

cover - WSDCC playground

Kids from impoverished sections of my city don’t often get to play in natural settings, since they typically live in apartment houses and buildings with little to no yard space. That has recently changed for some lucky preschoolers at the Webster Square Day Care Center here in Worcester, Massachusetts.

The center, which operates out of the lower level of a church, wanted to update their playground, which then consisted of scattered equipment within a sand surface. Originally their goal was to simply change the surfacing to a safer material that would be acceptable under current state requirements for day care centers. However, I convinced them to take the renovation a step further and add some nature-based features for a more enriching play experience.

My firm developed plans for this playground, and the day care center received several grants which funded the improvements over a period of a couple years. Since the budget was fairly limited, we retained the existing play equipment, keeping the larger pieces in their pre-existing locations and moving the smaller items. Plants, rocks, stepping stones, logs, water and sand play tables, musical chimes, and a vegetable garden were added to the space.

Although the playground is used exclusively by the day care center during the weekdays, it is open in the evenings and on weekends for use by neighborhood children. The kids get a lot of enjoyment out of this space, and I’m told that the natural features are particularly popular. A few “before” and “after” photos are included below to illustrate the improvements.

1 - before - west end A
BEFORE:  A couple of play panels, sand surfacing, weeds, and an ugly fence (owned by the neighbors) were all that existed on the west side of the playground. The wooded area behind the play area is on adjacent property.

 

2 - after - west end A
AFTER: Relocated play house, plants (including shrubs which will grow to hide the fence), stepping logs, & chimes. The drums are portable, stored in a nearby shed.

 


 

3 - before - west end B
BEFORE: West end of the playground

 

4 - after - west end B
AFTER:  Lots of enjoyment from a few simple features

 


 

5 - before - east end
BEFORE: East end of the playground

 

6 - after - east end
AFTER:  Rocks and plants create a space for imaginative play.

 


 

7 - before - central area
BEFORE:  Central section of playground

 

8 - after - central area
AFTER:  Existing play equipment was retained, engineered wood fiber safety surfacing was installed, and a sand table was added. An at-grade sand play area is situated behind the table.

 


 

9 - before - garden area
BEFORE:  Unused, weedy area west of the existing shed

 

10 - after - garden area
AFTER:  A raised vegetable garden for the children to learn about growing food
 
Photos by Alice Webb and the Webster Square Day Care Center staff

Deco Details

Straying once again from the subject of landscape architecture, I am posting some photos of my favorite style of historic architecture. Art Deco buildings are not very common in the northeastern U.S., and I always get excited when I see a well-designed structure in this style, especially those with interesting details. Below are a few examples I’ve photographed during the last couple of years. Also, you can check out more on this subject in two of my previous posts: Miami Beach Art Deco and Art Deco in New York City.
 
A - 111 Eighth Avenue NYC
111 Eighth Avenue building, New York City
 
B - American Radiator Bldg. NYC
American Radiator building, New York City
 
F - Film Center NYC
Film Center building, New York City
 
E - Higgins Armory Building, Worcester MA
Higgins Armory building (former museum), Worcester, MA
 
D - Empire Diner NYC
Empire Diner, New York City
 
G - Grand theater, Ellsworth ME
Grand Theater, Ellsworth, ME
 
H - Greenwich Substation NYC
Greenwich Substation, New York City
 
I - NET&T bldg in Worcester MA
New England Telephone and Telegraph Co. building, Worcester, MA
 
C - Coca cola bldg in Worcester MA
Coca Cola building (former bottling plant), Worcester, MA
 
J - Salvation Army Bldg. 1 NYC
Salvation Army building, New York City
 
K - Salvation Army Bldg. 2 NYC
Salvation Army building, New York City
 
L - Starrett-Lehigh Bldg. NYC
Starrett-Lehigh building, New York City
 
Photos by Alice Webb, except Higgins Armory building photo (obtained from Wikimedia Commons, and cropped).