Skid Steer Tree Spade Buying Guide: Carrier Compatibility, Hydraulic Requirements, and Top Models
Skid Steer Tree Spade Buying Guide: Carrier Compatibility, Hydraulic Requirements, and Top Models
Skid Steer Tree Spade Buying Guide: Carrier Compatibility, Hydraulic Requirements, and Top Models
A skid steer tree spade turns a machine you already own into a production tree-moving tool. Instead of buying a dedicated truck-mounted or trailer-mounted digger, you bolt a spade to the loader in your yard and dig, ball, and relocate nursery stock the same afternoon. For nurseries, tree services, landscapers, and municipal crews, that is the shortest path from “we need to move trees” to “we are moving trees.”
The catch is matching the spade to the carrier. A skid steer tree spade attachment only performs if the machine can supply the hydraulic flow, carry the load, and physically mount the unit. This guide walks through carrier compatibility across Bobcat, CAT, Kubota, and John Deere, the hydraulic flow and pressure a spade needs, how to size a spade to the trees you dig, and the Big John models that fit the skid-steer platform. Every spec below is pulled from Big John’s published product data.
What a Skid-Steer Tree Spade Is (and What It Is Not)
A skid steer tree spade is a hydraulic attachment with a ring of curved or straight blades that drive into the soil around a tree, close beneath the root ball, and lift the tree out intact. Big John’s skid-steer units are nursery diggers: they are built for prepared-ground nursery digging, where the soil is worked and consistent, not for cutting virgin hardpan or rocky ground. That distinction matters when you compare a skid-steer spade against a heavier truck-mounted machine.
The blades on Big John skid-steer spades are cold-formed from AR400 steel and fluted to distribute digging stress. The unit mounts to the loader’s quick-attach plate and runs off the machine’s auxiliary hydraulics. Big John offers three blade profiles: pointed (30 degrees), semi-truncated (25 degrees), and truncated (22 degrees). Pointed blades penetrate hard ground more aggressively; truncated blades reduce root-ball weight and overall height, which helps on lighter carriers.
A skid-steer tree spade is not a substitute for a full-size truck-mounted spade when you are moving trees larger than roughly 5 inches in trunk diameter. It is the right tool for nursery production, container-to-field work, and jobsite relocations where a compact, low-cost, high-cycle digger beats a big dedicated machine.
Carrier Compatibility: Bobcat, CAT, Kubota, John Deere
Most name-brand skid steers use the universal (ISO) quick-attach plate, so a Big John skid-steer spade physically mounts to Bobcat, CAT, Kubota, and John Deere machines. Compatibility comes down to three questions, in order: does the machine put out enough hydraulic flow, can it carry the operating weight and root-ball load, and is the coupler the standard type or a proprietary variant.
The table below is a planning reference. Verify your exact model’s auxiliary flow and rated operating capacity against the machine’s spec sheet before ordering, because output varies widely inside a single brand between standard-flow and high-flow trims and between radial-lift and vertical-lift frames.
| Carrier brand | Typical mount | Standard-flow vs high-flow | Fit notes |
|---|---|---|---|
| Bobcat | Bob-Tach / universal quick-attach | Both offered across the line | Broad model range; larger frame (R-Series) machines carry the bigger spades comfortably. Confirm your loader’s auxiliary GPM. |
| CAT | Universal quick-attach | Both offered across the line | Compact and larger frames available; a CAT skid steer tree spade pairing works well on higher-capacity models for the wider spades. |
| Kubota | Universal quick-attach | Standard flow common; high-flow on select models | A tree spade for a Kubota skid steer fits, but many mid-size Kubota loaders run standard flow, so match spade size to available GPM. |
| John Deere | Universal quick-attach | Both offered across the line | A John Deere tree spade attachment mounts on the standard coupler; larger G/P-Series machines handle the wider spades. |
Two carrier cautions. First, mini skid steers (compact track loaders under roughly 2,000 pounds operating capacity and stand-on units) are a different class. A tree spade for a mini skid steer exists in the market, but Big John’s skid-steer nursery diggers are sized for full-size skid steer loaders. If you run a mini, talk to Big John about the smallest models and confirm flow and weight before assuming a fit. Second, some machines use proprietary couplers; if yours is not the universal plate, confirm adapter availability.
Hydraulic Requirements: Flow and Pressure
The single most important number when buying a hydraulic tree spade for a skid steer is auxiliary hydraulic flow. Big John lists a minimum drive-system requirement of 10 to 16 GPM across its skid-steer nursery diggers, from the smallest Model 20 to the largest Model 54. If your loader’s auxiliary circuit sits below that range, the spade blades will drive slowly and the cycle will drag; below the minimum, it may not perform at all.
Match the spade to the flow you actually have:
- Standard-flow skid steers (roughly 10 to 20 GPM) run Big John skid-steer spades within the specified 10 to 16 GPM window on most models. This covers the majority of full-size loaders.
- High-flow skid steers (above roughly 20 GPM) have headroom to spare and will cycle a spade quickly, but you do not need high flow to run these units.
Pressure matters too. Skid steer auxiliary circuits generally run in the 3,000 to 3,500 PSI range, which is compatible with these attachments; Big John does not publish a separate minimum PSI for the skid-steer line, so confirm your specific unit’s pressure rating with the factory rather than assuming. Big John’s skid-steer spades ship with adjustable valve-body speed, so you can slow the spade down for a new operator or open it up for a seasoned one. An optional extra valve body lets you add hydraulic stabilizers or other components without robbing the main digging circuit.
Weight and carrier sizing
Hydraulics get you digging; carry capacity keeps you upright. Two weights drive carrier sizing: the spade’s own operating weight and the weight of a loaded root ball out in front of the machine. Big John publishes total machine weight and root-ball weight for each model. For example, the Model 44ST has a total machine weight of 2,400 pounds and a root-ball weight of 1,100 pounds, while the larger Model 54 carries a 2,400-pound root ball at a total machine weight of 3,000 pounds. Add those together, account for the load being cantilevered ahead of the coupler, and compare against your loader’s rated operating capacity. When the numbers are close, size up the carrier or size down the spade.
What Size Tree Spade for a Skid Steer
Size the spade to the largest tree you dig regularly, not the biggest tree you will ever touch once. Big John’s skid-steer nursery diggers span roughly 20 to 60 inches of root-ball width, and the practical trunk-diameter range across the line runs from 1 inch up to 5 inches. Here is how the published models map to tree size:
| Model | Trunk diameter | Root ball width | Number of spades |
|---|---|---|---|
| Model 20 | 1″ – 2″ | 20″ | 3 |
| Model 28 | 1″ – 3″ | (see product page) | 4 |
| Model 36 | 1″ – 3″ | (see product page) | 4 |
| Model 40 | 1″ – 4″ | (see product page) | 4 |
| Model 44 / 44ST | 1″ – 4″ | 44″ | 4 |
| Model 48 | 1″ – 5″ | (see product page) | 4 |
| Model 54 / 54ST | 1″ – 5″ | 54″ | 4 |
The general rule from arborist practice is that root-ball diameter should be roughly 10 to 12 inches of ball for every inch of trunk caliper, which is why a wider spade is required as trunk diameter climbs. ISA and university cooperative extension transplanting guidance point to the same relationship: undersize the ball and you strip too many roots for the tree to recover. Choosing the spade by root-ball width, then, is really choosing it by how large a tree you can move and keep alive.
A note on the “ST” designation. Big John lists standard and “ST” (short-tower) variants of several models. The 44ST, for example, runs a shorter blade tower (65 inches down versus 83 inches on the standard 44) and a shallower root ball (28 inches versus 36 inches), which trims root-ball weight to 1,100 pounds and lowers the digging profile. The tradeoff is a slightly heavier total machine weight (2,400 pounds versus 2,000). Short-tower units are worth a look where overhead clearance or a lower center of gravity matters.
Top Skid-Steer Tree Spade Models: Big John 30ST and 44ST
Big John is an American manufacturer building tree spades in Heber Springs, Arkansas, with a track record going back to the 1970s. Two of its skid-steer units come up most often for buyers weighing the best skid steer tree spade for nursery and jobsite work.
Big John 30ST
The 30ST is a 30-inch short-tower skid-steer spade. Big John currently lists a 30ST demo unit in its used-equipment inventory, set up to move trees with a wireless remote. As a 30-inch class machine, it slots between the Model 28 and Model 36 for root-ball width, which puts it in the small-to-mid range of trunk diameters for the line. It is a strong fit for a nursery digging smaller caliper stock in volume, or for a crew that wants a compact, lower-profile spade on a mid-size loader. Because the live listing is a used demo unit rather than a full spec page, confirm exact root-ball dimensions, weights, and blade profile with the factory before ordering.
Big John 44ST
The 44ST is one of the workhorses of the skid-steer line. Verified specs from Big John:
| Spec | Model 44 | 44ST |
|---|---|---|
| Tree trunk diameter | 1″ – 4″ | 1″ – 4″ |
| Root ball width (adjustable) | 44″ | 44″ |
| Root ball depth (adjustable) | 36″ | 28″ |
| Root ball weight | 1,200 lbs | 1,100 lbs |
| Total machine weight | 2,000 lbs | 2,400 lbs |
| Blade tower height (down) | 83″ | 65″ |
| Gate opening | 24″ | 21″ |
| Operating width (closed) | 96″ | 106″ |
| Number of spades | 4 | 4 |
| Hydraulic gate lock | Yes | Yes |
| Adjustable mechanical pads | Yes | Yes |
| Spade material | AR400 | AR400 |
| Drive system (minimum) | 10 – 16 GPM | 10 – 16 GPM |
The 44ST handles trees up to 4 inches in trunk diameter with a 44-inch root ball, four AR400 spades, a hydraulic gate lock, and adjustable mechanical pads standard. The short-tower design (65-inch blade tower down) keeps the profile low and the root ball lighter at 1,100 pounds. It is available in pointed, semi-truncated, and truncated blade profiles. For a nursery or tree service moving the bulk of its stock in the 2 to 4 inch range, the 44ST is often the sweet spot: enough capacity to be productive, light enough to run on a broad range of full-size loaders.
For crews moving larger stock, the Model 54 and 54ST push the range to 5-inch trunks and a 54-inch root ball while staying on the skid-steer platform, which is about as large a tree spade for a skid steer as the line offers.
Features Across the Line
Every Big John skid-steer tree spade attachment shares a common feature set:
- Wireless or cabled remote controls, so you can run the spade from the cab or from outside the machine.
- Heavy-duty gate hinges built for repeated hard-digging cycles.
- Durable slide blocks made from top-grade plastics, with fewer moving parts, no bolts to rust, and no small plastic parts to lose.
- Cold-formed, fluted AR400 blades for durability and even stress distribution.
- Adjustable valve-body speed and an optional extra valve body for add-on hydraulics like stabilizers.
Big John also offers customization: changing blade size, number, shape, or position, adding hydraulic stabilizers, and fitting adjustable leveling pads. If a stock model does not fit your ground or your carrier, the factory builds to spec.
Buying, Pricing, and Where to Look
Pricing on a skid steer tree spade for sale depends on model size, blade profile, and options like extra valve bodies or stabilizers, so there is no single sticker figure. Big John does not publish list prices online; the accurate way to get a number is a direct quote with your carrier and blade preference specified. If you are shopping a used skid steer tree spade, Big John maintains a used-equipment section, which is currently where the 30ST demo unit is listed. Used inventory turns over, so availability changes.
When you request a quote, have three things ready: your loader’s make, model, and auxiliary hydraulic flow (GPM); the largest trunk diameter you dig regularly; and your ground conditions (prepared nursery soil versus firmer ground), which drives the blade-profile choice.
Explore the full skid-steer lineup on the skid steer attachment page, see the current Big John 30ST listing in used equipment, and browse the broader tree spade range if you are also weighing truck-mounted, trailer-mounted, or loader-mounted machines.
Frequently Asked Questions
What hydraulic flow does a skid steer tree spade need?
Big John’s skid-steer nursery diggers list a minimum drive-system requirement of 10 to 16 GPM across the line, from the Model 20 to the Model 54. Most standard-flow skid steers fall inside that window. Confirm your loader’s auxiliary flow on its spec sheet before ordering, since output varies between standard-flow and high-flow trims.
What size tree spade should I get for my skid steer?
Size by root-ball width and trunk diameter. Big John’s skid-steer models run from a 20-inch root ball (1 to 2 inch trunks) up to a 54-inch root ball (1 to 5 inch trunks). Pick the spade that covers the largest tree you dig regularly. Arborist guidance calls for roughly 10 to 12 inches of root ball per inch of trunk caliper.
How big a tree can a skid steer tree spade move?
Big John’s skid-steer line handles trees from 1 inch up to about 5 inches in trunk diameter, with the Model 48 and Model 54 reaching the top of that range on a 54-inch root ball. For trees larger than roughly 5 inches, a truck-mounted or trailer-mounted spade is the better tool. Undersizing the root ball risks the tree’s survival.
Does a skid steer tree spade fit Bobcat, CAT, Kubota, and John Deere?
Yes. Big John skid-steer spades mount to the universal (ISO) quick-attach plate used by most Bobcat, CAT, Kubota, and John Deere skid steers. The real question is hydraulic flow and carry capacity, not the coupler. Verify your specific machine’s auxiliary GPM and rated operating capacity, and confirm your coupler is the standard type.
How do you use a skid steer tree spade?
Position the loader so the spade rings the tree, then drive the blades into the soil with the hydraulics until they close beneath the root ball. Lift the tree out intact, transport it, and set it in the new hole. Big John units run from a wireless or cabled remote and include a hydraulic gate lock. Most operators learn to dig a tree within minutes.
What is the difference between a Model 44 and a 44ST?
Both dig 1 to 4 inch trunks with a 44-inch root ball and four AR400 spades. The 44ST is the short-tower version: a 65-inch blade tower (down) versus 83 inches, a 28-inch root-ball depth versus 36 inches, and a lighter 1,100-pound root ball versus 1,200. The tradeoff is a heavier total machine weight, 2,400 pounds versus 2,000, on the ST.
Related Big John equipment and guides: the Big John 30ST skid-steer tree spade, the Big John 44ST skid-steer tree spade, skid steer tree spade attachments.
