diff --git a/provider/lpffi/sdr_funcs.go b/provider/lpffi/sdr_funcs.go
index 1dae5fa71..39b2dffde 100644
--- a/provider/lpffi/sdr_funcs.go
+++ b/provider/lpffi/sdr_funcs.go
@@ -103,3 +103,7 @@ func (sb *SealCalls) GenerateSDR(ctx context.Context, sector storiface.SectorRef
 
 	return nil
 }
+
+func (sb *SealCalls) TreeRC() {
+	ffi.SealPreCommitPhase2()
+}
diff --git a/provider/lpseal/poller.go b/provider/lpseal/poller.go
index c3222016d..a9f7b3ade 100644
--- a/provider/lpseal/poller.go
+++ b/provider/lpseal/poller.go
@@ -14,6 +14,7 @@ var log = logging.Logger("lpseal")
 
 const (
 	pollerSDR = iota
+	pollerTrees
 
 	numPollers
 )
diff --git a/provider/lpseal/task_sdr.go b/provider/lpseal/task_sdr.go
index 0afdc34d4..86efedafb 100644
--- a/provider/lpseal/task_sdr.go
+++ b/provider/lpseal/task_sdr.go
@@ -32,16 +32,16 @@ type SDRTask struct {
 
 	sc *lpffi.SealCalls
 
-	maxSDR int
+	max int
 }
 
 func NewSDRTask(api SDRAPI, db *harmonydb.DB, sp *SealPoller, sc *lpffi.SealCalls, maxSDR int) *SDRTask {
 	return &SDRTask{
-		api:    api,
-		db:     db,
-		sp:     sp,
-		sc:     sc,
-		maxSDR: maxSDR,
+		api: api,
+		db:  db,
+		sp:  sp,
+		sc:  sc,
+		max: maxSDR,
 	}
 }
 
@@ -163,14 +163,14 @@ func (s *SDRTask) CanAccept(ids []harmonytask.TaskID, engine *harmonytask.TaskEn
 
 func (s *SDRTask) TypeDetails() harmonytask.TaskTypeDetails {
 	res := harmonytask.TaskTypeDetails{
-		Max:  s.maxSDR,
+		Max:  s.max,
 		Name: "SDR",
 		Cost: resources.Resources{ // todo offset for prefetch?
 			Cpu: 4, // todo multicore sdr
 			Gpu: 0,
 			Ram: 54 << 30, // todo measure; lower on 2k devnetn
 		},
-		MaxFailures: 0,
+		MaxFailures: 2,
 		Follows:     nil,
 	}
 
diff --git a/provider/lpseal/task_trees.go b/provider/lpseal/task_trees.go
new file mode 100644
index 000000000..612794b99
--- /dev/null
+++ b/provider/lpseal/task_trees.go
@@ -0,0 +1,107 @@
+package lpseal
+
+import (
+	"context"
+	"github.com/filecoin-project/go-commp-utils/zerocomm"
+	"github.com/filecoin-project/go-state-types/abi"
+	"github.com/filecoin-project/lotus/lib/harmony/harmonydb"
+	"github.com/filecoin-project/lotus/lib/harmony/harmonytask"
+	"github.com/filecoin-project/lotus/lib/harmony/resources"
+	"github.com/filecoin-project/lotus/provider/lpffi"
+	"github.com/filecoin-project/lotus/storage/sealer/storiface"
+	"golang.org/x/xerrors"
+)
+
+type TreesTask struct {
+	sp *SealPoller
+	db *harmonydb.DB
+	sc *lpffi.SealCalls
+
+	max int
+}
+
+func (t *TreesTask) Do(taskID harmonytask.TaskID, stillOwned func() bool) (done bool, err error) {
+	ctx := context.Background()
+
+	var sectorParamsArr []struct {
+		SpID         int64                   `db:"sp_id"`
+		SectorNumber int64                   `db:"sector_number"`
+		RegSealProof abi.RegisteredSealProof `db:"reg_seal_proof"`
+	}
+
+	err = t.db.Select(ctx, &sectorParamsArr, `
+		SELECT sp_id, sector_number, reg_seal_proof
+		FROM sectors_sdr_pipeline
+		WHERE task_id_tree_r = $1 and task_id_tree_c = $1 and task_id_tree_d = $1`, taskID)
+	if err != nil {
+		return false, xerrors.Errorf("getting sector params: %w", err)
+	}
+
+	if len(sectorParamsArr) != 1 {
+		return false, xerrors.Errorf("expected 1 sector params, got %d", len(sectorParamsArr))
+	}
+	sectorParams := sectorParamsArr[0]
+
+	var pieces []struct {
+		PieceIndex int64  `db:"piece_index"`
+		PieceCID   string `db:"piece_cid"`
+		PieceSize  int64  `db:"piece_size"`
+	}
+
+	err = t.db.Select(ctx, &pieces, `
+		SELECT piece_index, piece_cid, piece_size
+		FROM sectors_sdr_initial_pieces
+		WHERE sp_id = $1 AND sector_number = $2`, sectorParams.SpID, sectorParams.SectorNumber)
+	if err != nil {
+		return false, xerrors.Errorf("getting pieces: %w", err)
+	}
+
+	if len(pieces) > 0 {
+		// todo sectors with data
+		return false, xerrors.Errorf("todo sectors with data")
+	}
+
+	ssize, err := sectorParams.RegSealProof.SectorSize()
+	if err != nil {
+		return false, xerrors.Errorf("getting sector size: %w", err)
+	}
+
+	commd := zerocomm.ZeroPieceCommitment(abi.PaddedPieceSize(ssize).Unpadded())
+
+	sref := storiface.SectorRef{
+		ID: abi.SectorID{
+			Miner:  abi.ActorID(sectorParams.SpID),
+			Number: abi.SectorNumber(sectorParams.SectorNumber),
+		},
+		ProofType: sectorParams.RegSealProof,
+	}
+
+	t.sc.
+}
+
+func (t *TreesTask) CanAccept(ids []harmonytask.TaskID, engine *harmonytask.TaskEngine) (*harmonytask.TaskID, error) {
+	// todo reserve storage
+
+	id := ids[0]
+	return &id, nil
+}
+
+func (t *TreesTask) TypeDetails() harmonytask.TaskTypeDetails {
+	return harmonytask.TaskTypeDetails{
+		Max:  t.max,
+		Name: "SDRTrees",
+		Cost: resources.Resources{
+			Cpu: 1,
+			Gpu: 1,
+			Ram: 8000, // todo
+		},
+		MaxFailures: 3,
+		Follows:     nil,
+	}
+}
+
+func (t *TreesTask) Adder(taskFunc harmonytask.AddTaskFunc) {
+	t.sp.pollers[pollerTrees].Set(taskFunc)
+}
+
+var _ harmonytask.TaskInterface = &TreesTask{}