The questions crews and program managers actually ask

A standard surface bag empties in 5–9 hours, then the soil dries until the next crew visit. Tree Guardian is a drop-in establishment kit installed at planting: its bag and wicking irrigation meter one fill into the root ball continuously for 7–10 days, and inoculated biochar plus mycorrhizal fungi improve the soil the tree roots into. Same crew, same truck, same fill — the water just lasts the full window between visits.

The bag itself is also designed around the tree, not against it: it leaves space for the root flare to breathe, with an opening so moisture isn’t trapped at the flare — a common rot and girdling risk with wrap-around trunk bags.

Best practice is a refill every seven days, and each 75-litre fill carries a three-day buffer beyond that. If a crew misses a Friday watering, they know the tree is still receiving moisture until Monday.

Published guidance calls for water every 2–3 days in the first season — a cadence no municipal route actually sustains. One fill covers the full best-practice cycle plus the buffer, so a weekly or even slightly slipped route keeps the root zone in the target band.

Pilot kits are $250 per tree; volume pricing is $150. For context, one failed street tree costs a city about $3,250 — establishment plus removal and replanting — so a single avoided failure covers thirteen pilot kits. The savings model walks through every assumption.

Minutes, at planting, by the same crew doing the planting: dig, place the pillow, connect, water in. No power, no plumbing, no electronics. See it done in the two-minute install video on the pilot page.

A 75-litre reservoir bag, a passive wicking-irrigation assembly that delivers water directly to the root ball, and a soil amendment of inoculated biochar and mycorrhizal fungi. Everything is passive — no pumps, batteries, or timers to maintain or fail. Full detail on how it works.

No. Crews fill it from the same truck, the same way they fill a surface bag today. The difference is what happens after they drive away: the kit meters that fill across the week instead of dumping it in hours.

The working components sit in the planting pit, below grade — there's less on the surface to slash, kick, or carry off than with a conventional surface bag. Vandalism and tamper rates are among the metrics the pilot tracks explicitly, so partner cities get measured numbers, not assurances.

The kit is designed for the establishment window, when watering drives survival. Best practice is to remove the bag for the winter season and redeploy it in spring — it preserves the durability of the bag, and it’s healthier for the tree.

Standard tree bags are known to trap moisture against the root flare and trunk in heavy rain. Ours is specifically designed with an opening so the root flare can breathe — but even so, removing it over winter is best for the tree. The soil amendments stay in the root zone and keep working for the life of the tree.

Matched controls: same species, same neighbourhoods, same planting window — half on Tree Guardian, half on your current practice. Survival is measured at 12 and 24 months, with simple photo and visit tracking, and wireless soil-moisture sensors as an optional add-on should you wish for more data. You test it with our guidance and review throughout, and the pilot is sized to your program; details on the pilot page.

Survival at 12 and 24 months versus matched controls, crew visits and time per tree, and canopy and field condition (including tampering) — all trackable with photos and existing crew logs. Wireless soil-moisture sensors are an optional add-on should you wish for more data. Just as valuable to us: your crews’ feedback, which shapes what we offer your program specifically. The goal is to replace every modelled number in the savings model with a measured one from your streets.