David Sivyer has some pretty tall responsibilities. And leafy.

As the forestry services manager, he oversees all of the forestry operations for the City of Milwaukee. He is ultimately responsible for the management of the 193,000 street trees (which are referred to as the "urban forest"), 120 miles of landscaped / irrigated boulevards and the 160-acre nursery (based in Franklin) that features a 30,000-square foot green house.

Sivyer also manages equipment repair, contract administration and code enforcement, which ensures trees and other vegetation on private properties or in vacant lots don’t obstruct streets, alleys or walkways.

In total, there are 107 urban forestry specialists, 22 crew leaders and eight technicians and inspectors, all of whom perform various arboricultural tasks.

The city plants about 3,600-4,000 new trees a year. Unfortunately, about the same amount are removed annually. Still, Sivyer says Milwaukee’s high replacement rate is rare.

"Milwaukee is unique. Almost all, about 98 percent, of our planting spaces that can accommodate a tree, have a tree," says Sivyer. "I don’t know what other city can boast that. It’s an incredibly high standard."

The benefits of having lots of trees are plentiful for residents and include protection from stormy weather, natural energy saving, better air quality and increased property values.

"The city made a commitment long ago that street trees are important to our infrastructure," he says.

Currently, the most common tree in Milwaukee is the Norway maple. There are about 1.4 million trees in the city, including those considered the urban forest.

It takes six years for the arborists to prune all of the trees. They do it systematically, block by block, and once they prune every tree on every street in the city, they start over again.

The pruning happens all year ‘round, including winter. Pruning gets delayed in the wintertime because the arborists are also the snow removers and salters and so, if Milwaukee gets a lot of snow, then the pruning process gets off schedule.

Currently, a big chunk of the arborists’ agenda revolves around proactively preventing Emerald Ash Borer disease by injecting trees with treatment.

Unfortunately, the disease, which was first discovered in Detroit in 2002, has spread to 18 states and two provinces and has already killed 100,000,000 trees world wide, including about 717,000 in Wisconsin.

"Luckily, we’ve done a lot to prepare ourselves for this since we first found out about it in 2002," says Sivyer.

The disease was found in Wisconsin in 2012 but the arborists had taken proactive measures – mainly treating as well as raising awareness with the public who might have ash trees on their private property – since 2009.

The teams are able to inject about 13,500 trees a year and they focus on ash trees that are at least 8-inches in diameter because the smaller the tree the easier to replace. Once again, Milwaukee is a leader in this branch of arboriculture.

"We are leading the nation in our strategy to manage this invasive pest," says Sivyer.

Trees are much more expensive to have taken down than to proactively treat, but it's up to Milwaukee residents with ash trees on their private land to identify and treat them. While the city cannot treat a privately owned ash, its forestry services has the responsibility of removing trees, at tax payer expense, that pose a danger to people and property.

Sivyer's fear, however, is that the disease will still spread more quickly than the department’s person power can handle and the dead trees will lose limbs or fall over before they can be safely removed, which is what happened with Dutch Elm Disease.

Dutch Elm Disease was first discovered in 1956 and it still affects elm trees today. Elms were very popular in the Midwest because they required minimal maintenance and had large canopies which provided a lot of shade, so when the disease struck, many areas lost all or most of their trees within a 55-year period.

More than 200,000 Milwaukee trees died from Dutch Elm, mostly in the ‘60s, ‘70s and ‘80s. The disease spread very quickly and there was not an effective treatment at the time. Today, through treatment and proactive care, arborists are better equipped to handle the epidemic, but the challenges remain.

Because the Dutch Elm epidemic was so major, arborists were unable to perform their regular pruning or planting practices for many years.

"For 17 years they were basically removing (sick or dead) elm trees," says Sivyer. "But we’re not going to go thorough this again."

The planting of trees has changed in light of previous diseases. In the past, neighborhoods planted the same type of tree, and now, the species are being diversified so when a disease occurs it doesn’t wipe out all of a community’s trees.

Sivyer has been in the industry for 30 years and in Milwaukee since 2006. He has two bachelor degrees – one in forestry and one in natural resources management – and a master’s degree in horticulture.

"I’ve always had a love for the outdoors and nature," he says. "Everywhere I go, I notice trees instead of people. It’s kind of a passion."

For the record, Sivyer confirms that you can, indeed, tell a tree’s age by counting the number of rings on a stump. The stump, however, can’t be taller than a foot, otherwise one must add a couple of years onto the number of tree rings.

"If a stump is three-feet-tall, it probably took three years for it to reach that height, so you have to keep that in mind. But with a low-to-the-ground stump, for most species, you can find out the age to the year," he says.

Sivyer says he likes the sugar maple the best, in terms of appearance and features, even though it’s not the best performer in street settings.

The OnMilwaukee editors dig trees, too, and here are their favorites:

Liz Lincoln Steiner
Copy editor

I can't say I have one specific favorite tree in Milwaukee. I always wanted a cool climbing tree in my yard as a kid, but neither of my parents had good ones. I have a love-hate relationship with the apple tree in my own back yard; my kids can climb it, their swing hangs from it, the white blossoms are beautiful and the apples we manage to collect make awesome applesauce. But it produces far more apples than we can use, so we end up with a yard full of apples half-eaten by raccoons.

The trees I enjoy most are fall trees, when the leaves turn bright, vibrant colors. Fall is my favorite season anyway, and the beautiful reds and oranges turn my neighborhood into a fiery landscape that I love.

Molly Snyder
Senior writer

I have always loved trees. One of my favorite books as a kid – and still today – was "The Giving Tree" by Shel Silverstein. (Even though when I read it to my kids, I inject that "the boy" wasn't very kind back to the tree.)

Trees have such a high-ranking place in my family's hearts that they've become quasi-spiritual and somehow, we started saying "trees!" when someone sneezes instead of "bless you."

My favorite tree is Wisconsin’s largest copper beech tree, located on the far north end of South Shore Park. Most of all, I like that it’s so climbable and I harbor fond memories of climbing it alone as well as with my family. The tree was planted in the mid-1800s and, as of a few years ago, it was 61-feet tall and 180 inches in circumference. I particularly like the roots of the tree which look like elephant feet to me. I also love that, when sitting in this tree, I get a great view of the lake.

Bobby Tanzilo
Managing editor

I'd be remiss if I didn't give props to the trees that provide me apples and hazelnuts (though that's more a bush, in all honesty), and the ash trees, red maple and black walnut that offer me shade on a hot summer day. But my real favorite is a craggy, off-kilter weeping beech that owns some prime real estate on Terrace and North, in the shadow of the Northpoint Water Tower, overlooking Lake Michigan. Its sloping shape and droopy branches make it look a bit like a leafy green Snuffleupagus. You can slip under its branches into the shade of the leaves and feel like you're in another place. While you're under there check out the tree's gnarly stem. For a few years I was always a bit panicked in spring because the tree gets its leaves later than the maples and other trees nearby. I feared it was dead until I realized it's just a late bloomer. When I drove past recently, I could just the leaves starting to emerge.

Matt Mueller
Pop culture editor

It's easy to take trees for granted. They're easy to miss when they're around – and even easier to miss in a different way when they're gone. Luckily, my favorite tree is still around: a big old willow tree in my childhood home's backyard. There's nothing particularly special about it – no unique shape or anything like that – but it's still very special to me. I essentially grew up around it, either swinging from a tire swing dangling from one of its thick branches or having it beautifully loom and sway over my dad, my sister and I as we played catch under its watch.

Over the years and over several big storms, the willow has taken a beating. The branch that once held the tire swing gave out – along with several other branches – during one big burst, and, like almost all of us, its once strong posture has begun to slump and waiver with time. In fact, when I visit my parents, there's a small voice in the back of my head always saying, "Man, if that thing ever topples over ...". But no bother, it's still the best tree. It can't provide any fruits or nuts, but it provided me with plenty of shade over the years – plus one other invaluable resource: memories.