How to re-create/ revive trees after they die?

//************************************************************************************************
//*                                                                                              *
//*                                Tree Revival System                                           *
//*                                    by Spinnaker                                              *
//*                                                                                              *
//************************************************************************************************



//*************************************************************************
//*
//* Globals required
//*
//*************************************************************************


    //* udg_TreeRevivalTrig                      Trigger for handling the revive actions
    //* udg_TRhash                               Hashtable for timer issues
    //* udg_dummyh                               Dummy harvester for IsDestructibleTree function
    

//* Configurable function for delay before tree gets resurrected     
    constant function TreeReviveDelay takes nothing returns real
        return 5.
    endfunction

//* Tells if birth animation should be shown while resurrecting a tree
    constant function TreeShowAnimation takes nothing returns boolean
        return true
    endfunction

   
//* System itself
function TrCallback takes nothing returns nothing
    local timer t = GetExpiredTimer()
    local destructable d = LoadDestructableHandle(udg_TRhash, GetHandleId(t), 0)
    call DestructableRestoreLife(d, GetDestructableMaxLife(d), TreeShowAnimation())
    call PauseTimer(t)
    call DestroyTimer(t)
    call FlushChildHashtable(udg_TRhash, GetHandleId(t))
    set d = null
    set t = null
endfunction
    
function CallTreeRevive takes nothing returns boolean
    local timer t = CreateTimer()
    call SaveDestructableHandle(udg_TRhash, GetHandleId(t), 0, GetTriggerDestructable())
    call TimerStart(t, TreeReviveDelay(), false, function TrCallback)
    set t = null
    return false
endfunction

function IsDestructableTree takes destructable dest returns boolean
    return IssueTargetOrderById(udg_dummyh, 852018, dest)
endfunction

function CallAddTree takes nothing returns nothing
    if IsDestructableTree(GetEnumDestructable()) then
        call TriggerRegisterDeathEvent(udg_TreeReviveTrig, GetEnumDestructable())
    endif
endfunction

//***************************************************************************
function InitTrig_TreeRevive takes nothing returns nothing
    set udg_TreeReviveTrig = CreateTrigger()
    set udg_TRhash = InitHashtable() 

  //* Actions required for IsDestructibleTree function
    set udg_dummyh = CreateUnit(Player(15), 'uloc', 0., 0., 0.)
    call ShowUnit(udg_dummyh, false)
    call UnitAddAbility(udg_dummyh, 'Ahrl')
    call UnitRemoveAbility(udg_dummyh, 'Amov')

  //* Revival setup
    call EnumDestructablesInRect(bj_mapInitialPlayableArea, null, function CallAddTree)
    call TriggerAddCondition(udg_TreeReviveTrig, Condition(function CallTreeRevive))
endfunction

function RegisterDestDeathInRegionEnum takes nothing returns nothing
    set bj_destInRegionDiesCount = bj_destInRegionDiesCount + 1
    if (bj_destInRegionDiesCount <= bj_MAX_DEST_IN_REGION_EVENTS) then
        call TriggerRegisterDeathEvent(bj_destInRegionDiesTrig, GetEnumDestructable())
    endif
endfunction

function TriggerRegisterDestDeathInRegionEvent takes trigger trig, rect r returns event
    set bj_destInRegionDiesTrig = trig
    set bj_destInRegionDiesCount = 0
    call EnumDestructablesInRect(r, null, function RegisterDestDeathInRegionEnum)
    return trig
endfunction